feat(vendors): add admin-assigned vendor company Area

Seed an organization-wide Area catalogue (East, Central, West, California)
with stable ids, add a nullable AreaId to VendorCompany, allow only Admins
to change it through the roster endpoints, expose areas facet metadata and
an areas[n] company-directory filter with the __unassigned__ sentinel.

Api.SeaHavenIndustries.Tests/VendorCompanyRosterControllerTests.cs

@@ -105,14 +105,14 @@ public class VendorCompanyRosterControllerTests
         var result = await controller.Create(new CreateVendorRosterDTO { Name = "Acme", Email = "acme@example.com" }, CancellationToken.None);
 
         result.Should().BeOfType<UnauthorizedObjectResult>();
-        service.Verify(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), It.IsAny<string>(), It.IsAny<CancellationToken>()), Times.Never);
+        service.Verify(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), It.IsAny<string>(), It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()), Times.Never);
     }
 
     [Fact]
     public async Task Create_Returns200()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ReturnsAsync(SampleRoster());
 
         var result = await NewController(service).Create(new CreateVendorRosterDTO { Name = "Acme", Email = "acme@example.com" }, CancellationToken.None);
@@ -125,7 +125,7 @@ public class VendorCompanyRosterControllerTests
     public async Task Create_ValidationException_Returns400()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new ValidationException("At least one company phone or email is required."));
 
         var result = await NewController(service).Create(new CreateVendorRosterDTO { Name = "Acme" }, CancellationToken.None);
@@ -137,7 +137,7 @@ public class VendorCompanyRosterControllerTests
     public async Task Create_DuplicateName_ReturnsStable409()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new VendorRosterDuplicateNameException(
                 "database detail",
                 new InvalidOperationException("IX_VendorCompanies_NormalizedName")));
@@ -164,14 +164,14 @@ public class VendorCompanyRosterControllerTests
         var result = await controller.Reconcile(7, new ReconcileVendorRosterDTO { RowVersion = "AAAAAAAAD8I=", Name = "Acme", Email = "acme@example.com" }, CancellationToken.None);
 
         result.Should().BeOfType<UnauthorizedObjectResult>();
-        service.Verify(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), It.IsAny<string>(), It.IsAny<CancellationToken>()), Times.Never);
+        service.Verify(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), It.IsAny<string>(), It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()), Times.Never);
     }
 
     [Fact]
     public async Task Reconcile_ValidationException_Returns400()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new ValidationException("Duplicate technician ids are not allowed."));
 
         var result = await NewController(service).Reconcile(7, new ReconcileVendorRosterDTO { RowVersion = "AAAAAAAAD8I=", Name = "Acme", Email = "acme@example.com" }, CancellationToken.None);
@@ -183,7 +183,7 @@ public class VendorCompanyRosterControllerTests
     public async Task Reconcile_CompanyNotFound_Returns404()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new KeyNotFoundException("not found"));
 
         var result = await NewController(service).Reconcile(404, new ReconcileVendorRosterDTO { RowVersion = "AAAAAAAAD8I=", Name = "Acme", Email = "acme@example.com" }, CancellationToken.None);
@@ -199,7 +199,7 @@ public class VendorCompanyRosterControllerTests
             new() { WorkOrderId = 500, WorkOrderNumber = "WO-500", LifecycleStatus = LifecycleStatus.Scheduled }
         };
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new VendorRosterConflictException("blocked", blocked));
 
         var result = await NewController(service).Reconcile(7, new ReconcileVendorRosterDTO { RowVersion = "AAAAAAAAD8I=", Name = "Acme", Email = "acme@example.com" }, CancellationToken.None);
@@ -212,7 +212,7 @@ public class VendorCompanyRosterControllerTests
     public async Task Reconcile_StaleRowVersion_ReturnsStable409WithoutExceptionText()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.ReconcileRosterAsync(It.IsAny<int>(), It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new DbUpdateConcurrencyException("internal provider detail: UPDATE [VendorCompanies] ..."));
 
         var result = await NewController(service).Reconcile(7, new ReconcileVendorRosterDTO { RowVersion = "AAAAAAAAD8I=", Name = "Acme", Email = "acme@example.com" }, CancellationToken.None);
@@ -251,14 +251,14 @@ public class VendorCompanyRosterControllerTests
         var result = await controller.AddTechnicians(7, PatchDto(), CancellationToken.None);
 
         result.Should().BeOfType<UnauthorizedObjectResult>();
-        service.Verify(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), It.IsAny<string>(), It.IsAny<CancellationToken>()), Times.Never);
+        service.Verify(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), It.IsAny<string>(), It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()), Times.Never);
     }
 
     [Fact]
     public async Task Patch_AddsTechnicians_Returns200WithRoster()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.AddTechniciansAsync(7, It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.AddTechniciansAsync(7, It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ReturnsAsync(SampleRoster());
 
         var result = await NewController(service).AddTechnicians(7, PatchDto(), CancellationToken.None);
@@ -272,7 +272,7 @@ public class VendorCompanyRosterControllerTests
     public async Task Patch_ValidationException_Returns400()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new ValidationException("Technician ids are not allowed when adding technicians."));
 
         var result = await NewController(service).AddTechnicians(7, PatchDto(), CancellationToken.None);
@@ -285,7 +285,7 @@ public class VendorCompanyRosterControllerTests
     public async Task Patch_CompanyNotFound_Returns404()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new KeyNotFoundException("not found"));
 
         var result = await NewController(service).AddTechnicians(404, PatchDto(), CancellationToken.None);
@@ -297,7 +297,7 @@ public class VendorCompanyRosterControllerTests
     public async Task Patch_StaleRowVersion_ReturnsStable409WithoutExceptionText()
     {
         var service = new Mock<IVendorCompanyRosterService>();
-        service.Setup(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<CancellationToken>()))
+        service.Setup(x => x.AddTechniciansAsync(It.IsAny<int>(), It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
             .ThrowsAsync(new DbUpdateConcurrencyException("internal provider detail: UPDATE [VendorCompanies] ..."));
 
         var result = await NewController(service).AddTechnicians(7, PatchDto(), CancellationToken.None);
@@ -306,4 +306,29 @@ public class VendorCompanyRosterControllerTests
         conflict.StatusCode.Should().Be(StatusCodes.Status409Conflict);
         conflict.Value!.ToString()!.Should().NotContain("internal provider detail");
     }
+
+    [Fact]
+    public async Task AreaAssignmentForbidden_Returns403OnEveryMutation()
+    {
+        var service = new Mock<IVendorCompanyRosterService>();
+        service.Setup(x => x.CreateRosterAsync(It.IsAny<CreateVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
+            .ThrowsAsync(new VendorAreaAssignmentForbiddenException());
+        service.Setup(x => x.ReconcileRosterAsync(7, It.IsAny<ReconcileVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
+            .ThrowsAsync(new VendorAreaAssignmentForbiddenException());
+        service.Setup(x => x.AddTechniciansAsync(7, It.IsAny<AddTechniciansVendorRosterDTO>(), "42", It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
+            .ThrowsAsync(new VendorAreaAssignmentForbiddenException());
+        var controller = NewController(service);
+
+        var results = new[]
+        {
+            await controller.Create(new CreateVendorRosterDTO { Name = "Acme", Email = "acme@example.com", AreaId = 1 }, CancellationToken.None),
+            await controller.Reconcile(7, new ReconcileVendorRosterDTO { RowVersion = "AAAAAAAAD8I=", Name = "Acme", AreaId = 1 }, CancellationToken.None),
+            await controller.AddTechnicians(7, new AddTechniciansVendorRosterDTO { RowVersion = "AAAAAAAAD8I=" }, CancellationToken.None)
+        };
+
+        foreach (var result in results)
+            result.Should().BeOfType<ObjectResult>().Which.StatusCode.Should().Be(StatusCodes.Status403Forbidden);
+
+        service.Verify(x => x.ReconcileRosterAsync(7, It.IsAny<ReconcileVendorRosterDTO>(), "42", controller.User, It.IsAny<CancellationToken>()), Times.Once);
+    }
 }

Api.SeaHavenIndustries.Tests/VendorCompanyRosterDataServiceTests.cs

@@ -835,4 +835,43 @@ public class VendorCompanyRosterDataServiceTests
 
         await act.Should().ThrowAsync<OperationCanceledException>();
     }
+
+    [Fact]
+    public async Task SaveRoster_AppliesAreaOnlyWhenProvidedAndReadsAreaName()
+    {
+        var dbName = Guid.NewGuid().ToString();
+        using var context = NewContext(dbName);
+        context.Areas.AddRange(
+            new Area { Id = 1, Name = "East", NormalizedName = "east" },
+            new Area { Id = 2, Name = "Central", NormalizedName = "central" });
+        await context.SaveChangesAsync();
+        var (companyId, _) = await SeedCompanyWithTechnicianAsync(context, "Area Co", "Tech");
+        var service = new VendorCompanyRosterDataService(context);
+
+        VendorCompanyRosterWriteModel Snapshot(bool provided, int? areaId) => new()
+        {
+            CompanyId = companyId,
+            Name = "Area Co",
+            Email = "area@example.com",
+            AreaIdProvided = provided,
+            AreaId = areaId,
+            Technicians = context.Vendors.Where(v => v.CompanyId == companyId)
+                .Select(v => new RosterTechnicianWriteModel { Id = v.Id, ContactName = v.ContactName })
+                .ToList()
+        };
+
+        var assigned = await service.SaveRosterAsync(Snapshot(true, 2), CancellationToken.None);
+        assigned.AreaId.Should().Be(2);
+        assigned.AreaName.Should().Be("Central");
+
+        var untouched = await service.SaveRosterAsync(Snapshot(false, null), CancellationToken.None);
+        untouched.AreaId.Should().Be(2);
+
+        var cleared = await service.SaveRosterAsync(Snapshot(true, null), CancellationToken.None);
+        cleared.AreaId.Should().BeNull();
+        cleared.AreaName.Should().BeNull();
+
+        (await service.IsActiveAreaAsync(1, CancellationToken.None)).Should().BeTrue();
+        (await service.IsActiveAreaAsync(42, CancellationToken.None)).Should().BeFalse();
+    }
 }

Api.SeaHavenIndustries.Tests/VendorCompanyRosterServiceTests.cs

@@ -3,6 +3,7 @@ using FluentAssertions;
 using FluentValidation;
 using Microsoft.Extensions.DependencyInjection;
 using Moq;
+using System.Security.Claims;
 using SeaHaven.DataServices.Interfaces;
 using SeaHaven.DataServices.Models;
 using SeaHaven.Services.DTOs;
@@ -13,6 +14,13 @@ namespace Api.SeaHavenIndustries.Tests;
 
 public class VendorCompanyRosterServiceTests
 {
+    private static readonly ClaimsPrincipal Dispatcher = Principal("User");
+    private static readonly ClaimsPrincipal Admin = Principal("Admin");
+
+    private static ClaimsPrincipal Principal(string role) => new(new ClaimsIdentity(
+        new[] { new Claim(ClaimTypes.NameIdentifier, "42"), new Claim(ClaimTypes.Role, role) },
+        "Test"));
+
     private static VendorCompanyRosterService NewService(Mock<IVendorCompanyRosterDataService> data) => new(data.Object);
 
     private static VendorCompanyRosterReadModel SampleReadModel(int companyId = 7, params int[] technicianIds) => new()
@@ -48,7 +56,7 @@ public class VendorCompanyRosterServiceTests
         var data = new Mock<IVendorCompanyRosterDataService>();
         var dto = new CreateVendorRosterDTO { Name = "Acme" };
 
-        var act = () => NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         await act.Should().ThrowAsync<ValidationException>();
         data.Verify(x => x.CreateRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
@@ -60,7 +68,7 @@ public class VendorCompanyRosterServiceTests
         var data = new Mock<IVendorCompanyRosterDataService>();
         var dto = new CreateVendorRosterDTO { Name = "Acme", CompanyPhone = "not-a-phone" };
 
-        var act = () => NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(error => error.PropertyName == nameof(CreateVendorRosterDTO.CompanyPhone));
@@ -78,7 +86,7 @@ public class VendorCompanyRosterServiceTests
             Technicians = new List<RosterTechnicianInputDTO> { new() { Id = 7, ContactName = "Riley" } }
         };
 
-        var act = () => NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         await act.Should().ThrowAsync<ValidationException>();
         data.Verify(x => x.CreateRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
@@ -98,7 +106,7 @@ public class VendorCompanyRosterServiceTests
             Name = "Acme",
             Email = "acme@example.com",
             Technicians = new List<RosterTechnicianInputDTO>()
-        }, "42", CancellationToken.None);
+        }, "42", Dispatcher, CancellationToken.None);
 
         captured.Should().NotBeNull();
         captured!.Technicians.Should().BeEmpty();
@@ -120,7 +128,7 @@ public class VendorCompanyRosterServiceTests
             Name = "Acme",
             Email = "acme@example.com",
             Notes = notes
-        }, "42", CancellationToken.None);
+        }, "42", Dispatcher, CancellationToken.None);
 
         captured!.Notes.Should().Be(notes);
     }
@@ -136,7 +144,7 @@ public class VendorCompanyRosterServiceTests
             Notes = new string('n', 501)
         };
 
-        var act = () => NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().ContainSingle(error =>
@@ -163,7 +171,7 @@ public class VendorCompanyRosterServiceTests
             }
         };
 
-        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         await act.Should().ThrowAsync<ValidationException>();
         data.Verify(x => x.SaveRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
@@ -188,7 +196,7 @@ public class VendorCompanyRosterServiceTests
             }
         };
 
-        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         await act.Should().ThrowAsync<ValidationException>();
         data.Verify(x => x.SaveRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
@@ -205,7 +213,7 @@ public class VendorCompanyRosterServiceTests
             GoogleMapsUrl = "http://maps.google.com/acme"
         };
 
-        var act = () => NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(e => e.PropertyName == nameof(CreateVendorRosterDTO.GoogleMapsUrl));
@@ -228,7 +236,7 @@ public class VendorCompanyRosterServiceTests
             {
                 new() { ContactName = "Riley", Phone = "+1 312 555 0100" }
             }
-        }, "42", CancellationToken.None);
+        }, "42", Dispatcher, CancellationToken.None);
 
         captured!.Technicians.Single().Phone.Should().Be("(312) 555-0100");
     }
@@ -247,7 +255,7 @@ public class VendorCompanyRosterServiceTests
             }
         };
 
-        var act = () => NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(e => e.PropertyName.EndsWith(nameof(RosterTechnicianInputDTO.Phone)));
@@ -270,7 +278,7 @@ public class VendorCompanyRosterServiceTests
             Name = "Acme Co",
             Email = "acme@example.com",
             Technicians = new List<RosterTechnicianInputDTO> { new() { Id = 1, ContactName = "T" } }
-        }, "42", CancellationToken.None);
+        }, "42", Dispatcher, CancellationToken.None);
 
         captured.Should().NotBeNull();
         captured!.CompanyId.Should().Be(7);
@@ -294,7 +302,7 @@ public class VendorCompanyRosterServiceTests
             Name = "Acme",
             Email = "acme@example.com",
             Notes = notes
-        }, "42", CancellationToken.None);
+        }, "42", Dispatcher, CancellationToken.None);
 
         captured!.Notes.Should().Be(notes);
     }
@@ -311,7 +319,7 @@ public class VendorCompanyRosterServiceTests
             Notes = new string('n', 501)
         };
 
-        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().ContainSingle(error =>
@@ -336,7 +344,7 @@ public class VendorCompanyRosterServiceTests
             Email = "acme@example.com"
         };
 
-        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(e => e.PropertyName == nameof(ReconcileVendorRosterDTO.RowVersion));
@@ -354,7 +362,7 @@ public class VendorCompanyRosterServiceTests
             Email = "acme@example.com"
         };
 
-        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(error => error.PropertyName == nameof(ReconcileVendorRosterDTO.RowVersion));
@@ -376,7 +384,7 @@ public class VendorCompanyRosterServiceTests
             Technicians = null!
         };
 
-        await NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        await NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         captured!.Technicians.Should().BeEmpty();
     }
@@ -397,7 +405,7 @@ public class VendorCompanyRosterServiceTests
             }
         };
 
-        var act = () => NewService(data).CreateRosterAsync(dto, "42", CancellationToken.None);
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
 
         await act.Should().ThrowAsync<ValidationException>();
         data.Verify(x => x.CreateRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
@@ -420,7 +428,7 @@ public class VendorCompanyRosterServiceTests
             {
                 new() { ContactName = "", Phone = "", PreferredContact = "Phone" }
             }
-        }, "42", CancellationToken.None);
+        }, "42", Dispatcher, CancellationToken.None);
 
         captured!.Technicians.Should().ContainSingle();
         captured.Technicians.Single().ContactName.Should().BeEmpty();
@@ -442,7 +450,7 @@ public class VendorCompanyRosterServiceTests
             Technicians = new List<RosterTechnicianInputDTO> { new() { Id = 1, ContactName = "T" } }
         };
 
-        var act = () => NewService(data).ReconcileRosterAsync(404, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).ReconcileRosterAsync(404, dto, "42", Dispatcher, CancellationToken.None);
         await act.Should().ThrowAsync<ValidationException>();
     }
 
@@ -462,7 +470,7 @@ public class VendorCompanyRosterServiceTests
             Name = "Acme",
             Email = "acme@example.com",
             Technicians = new List<RosterTechnicianInputDTO> { new() { Id = 1, ContactName = "T" } }
-        }, "42", cts.Token);
+        }, "42", Dispatcher, cts.Token);
 
         data.Verify(x => x.SaveRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), cts.Token), Times.Once);
     }
@@ -477,7 +485,7 @@ public class VendorCompanyRosterServiceTests
     public async Task AddTechnicians_WithoutAuthenticatedUser_Throws()
     {
         var data = new Mock<IVendorCompanyRosterDataService>();
-        var act = () => NewService(data).AddTechniciansAsync(7, AddDto(new RosterTechnicianInputDTO { ContactName = "T" }), "", CancellationToken.None);
+        var act = () => NewService(data).AddTechniciansAsync(7, AddDto(new RosterTechnicianInputDTO { ContactName = "T" }), "", Dispatcher, CancellationToken.None);
         await act.Should().ThrowAsync<UnauthorizedAccessException>();
         data.Verify(x => x.AddTechniciansAsync(It.IsAny<VendorCompanyRosterAddWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
     }
@@ -488,7 +496,7 @@ public class VendorCompanyRosterServiceTests
         var data = new Mock<IVendorCompanyRosterDataService>();
         var dto = AddDto(new RosterTechnicianInputDTO { Id = 999, ContactName = "Foreign" });
 
-        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(e => e.PropertyName == nameof(AddTechniciansVendorRosterDTO.AddTechnicians));
@@ -501,7 +509,7 @@ public class VendorCompanyRosterServiceTests
         var data = new Mock<IVendorCompanyRosterDataService>();
         var dto = new AddTechniciansVendorRosterDTO { RowVersion = "AAAAAAAAD8I=" };
 
-        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         await act.Should().ThrowAsync<ValidationException>();
         data.Verify(x => x.AddTechniciansAsync(It.IsAny<VendorCompanyRosterAddWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
@@ -517,7 +525,7 @@ public class VendorCompanyRosterServiceTests
             AddTechnicians = new List<RosterTechnicianInputDTO> { new() { ContactName = "T" } }
         };
 
-        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(e => e.PropertyName == nameof(AddTechniciansVendorRosterDTO.RowVersion));
@@ -530,7 +538,7 @@ public class VendorCompanyRosterServiceTests
         var data = new Mock<IVendorCompanyRosterDataService>();
         var dto = AddDto(new RosterTechnicianInputDTO { ContactName = "T", Phone = "555-1234" });
 
-        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().Contain(e => e.PropertyName.EndsWith(nameof(RosterTechnicianInputDTO.Phone)));
@@ -560,7 +568,7 @@ public class VendorCompanyRosterServiceTests
             }
         };
 
-        await NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        await NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         captured.Should().NotBeNull();
         captured!.CompanyId.Should().Be(7);
@@ -590,7 +598,7 @@ public class VendorCompanyRosterServiceTests
         {
             RowVersion = "AAAAAAAAD8I=",
             CompanyFields = new VendorRosterCompanyFieldsDTO { Notes = notes }
-        }, "42", CancellationToken.None);
+        }, "42", Dispatcher, CancellationToken.None);
 
         captured!.CompanyFields!.Notes.Should().Be(notes);
     }
@@ -605,7 +613,7 @@ public class VendorCompanyRosterServiceTests
             CompanyFields = new VendorRosterCompanyFieldsDTO { Notes = new string('n', 501) }
         };
 
-        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         (await act.Should().ThrowAsync<ValidationException>())
             .Which.Errors.Should().ContainSingle(error =>
@@ -632,7 +640,7 @@ public class VendorCompanyRosterServiceTests
             CompanyFields = new VendorRosterCompanyFieldsDTO { CompanyPhone = "   ", Email = "" }
         };
 
-        await NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        await NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         // SH-250: every field is blank, so there is no company change to apply. Forwarding a
         // non-null write model made the data layer bump RowVersion and rewrite every
@@ -652,7 +660,7 @@ public class VendorCompanyRosterServiceTests
             CompanyFields = new VendorRosterCompanyFieldsDTO { CompanyPhone = "   ", Email = "" }
         };
 
-        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         await act.Should().ThrowAsync<ValidationException>();
         data.Verify(
@@ -676,7 +684,7 @@ public class VendorCompanyRosterServiceTests
             CompanyFields = new VendorRosterCompanyFieldsDTO { City = "Norfolk" }
         };
 
-        await NewService(data).AddTechniciansAsync(7, dto, "42", CancellationToken.None);
+        await NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
 
         captured!.CompanyFields.Should().NotBeNull();
         captured.CompanyFields!.City.Should().Be("Norfolk");
@@ -690,8 +698,182 @@ public class VendorCompanyRosterServiceTests
             .ReturnsAsync(SampleReadModel(7, 1));
 
         using var cts = new CancellationTokenSource();
-        await NewService(data).AddTechniciansAsync(7, AddDto(new RosterTechnicianInputDTO { ContactName = "T" }), "42", cts.Token);
+        await NewService(data).AddTechniciansAsync(7, AddDto(new RosterTechnicianInputDTO { ContactName = "T" }), "42", Dispatcher, cts.Token);
 
         data.Verify(x => x.AddTechniciansAsync(It.IsAny<VendorCompanyRosterAddWriteModel>(), cts.Token), Times.Once);
     }
+
+    private static VendorCompanyRosterReadModel ReadModelWithArea(int? areaId)
+    {
+        var model = SampleReadModel(7, 1);
+        model.AreaId = areaId;
+        return model;
+    }
+
+    [Fact]
+    public async Task Create_NonAdminAssigningArea_IsForbiddenAndNotPersisted()
+    {
+        var data = new Mock<IVendorCompanyRosterDataService>();
+        var dto = new CreateVendorRosterDTO { Name = "Acme", Email = "acme@example.com", AreaId = 1 };
+
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Dispatcher, CancellationToken.None);
+
+        await act.Should().ThrowAsync<VendorAreaAssignmentForbiddenException>();
+        data.Verify(x => x.CreateRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
+    }
+
+    [Fact]
+    public async Task Create_AdminAssigningUnknownOrArchivedArea_ThrowsValidation()
+    {
+        var data = new Mock<IVendorCompanyRosterDataService>();
+        data.Setup(x => x.IsActiveAreaAsync(99, It.IsAny<CancellationToken>())).ReturnsAsync(false);
+        var dto = new CreateVendorRosterDTO { Name = "Acme", Email = "acme@example.com", AreaId = 99 };
+
+        var act = () => NewService(data).CreateRosterAsync(dto, "42", Admin, CancellationToken.None);
+
+        (await act.Should().ThrowAsync<ValidationException>())
+            .Which.Errors.Should().Contain(error => error.PropertyName == nameof(CreateVendorRosterDTO.AreaId));
+        data.Verify(x => x.CreateRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
+    }
+
+    [Fact]
+    public async Task Create_AdminAssigningActiveArea_PersistsAreaId()
+    {
+        using var cts = new CancellationTokenSource();
+        var data = new Mock<IVendorCompanyRosterDataService>();
+        data.Setup(x => x.IsActiveAreaAsync(2, cts.Token)).ReturnsAsync(true);
+        VendorCompanyRosterWriteModel? captured = null;
+        data.Setup(x => x.CreateRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()))
+            .Callback<VendorCompanyRosterWriteModel, CancellationToken>((model, _) => captured = model)
+            .ReturnsAsync(ReadModelWithArea(2));
+
+        var result = await NewService(data).CreateRosterAsync(
+            new CreateVendorRosterDTO { Name = "Acme", Email = "acme@example.com", AreaId = 2 },
+            "42",
+            Admin,
+            cts.Token);
+
+        captured!.AreaId.Should().Be(2);
+        result.AreaId.Should().Be(2);
+        data.Verify(x => x.IsActiveAreaAsync(2, cts.Token), Times.Once);
+    }
+
+    [Fact]
+    public async Task Reconcile_NonAdminChangingOrClearingArea_IsForbiddenAndNotPersisted()
+    {
+        var data = new Mock<IVendorCompanyRosterDataService>();
+        data.Setup(x => x.GetRosterAsync(null, 7, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(ReadModelWithArea(1));
+
+        foreach (int? requested in new int?[] { 3, null })
+        {
+            var dto = new ReconcileVendorRosterDTO
+            {
+                RowVersion = "AAAAAAAAD8I=",
+                Name = "Acme",
+                Email = "acme@example.com",
+                AreaId = requested
+            };
+
+            var act = () => NewService(data).ReconcileRosterAsync(7, dto, "42", Dispatcher, CancellationToken.None);
+
+            await act.Should().ThrowAsync<VendorAreaAssignmentForbiddenException>();
+        }
+
+        data.Verify(x => x.SaveRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
+    }
+
+    [Fact]
+    public async Task Reconcile_NonAdminRoundTripOrOmittedArea_SavesOtherFields()
+    {
+        var data = new Mock<IVendorCompanyRosterDataService>();
+        data.Setup(x => x.GetRosterAsync(null, 7, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(ReadModelWithArea(1));
+        var captured = new List<VendorCompanyRosterWriteModel>();
+        data.Setup(x => x.SaveRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()))
+            .Callback<VendorCompanyRosterWriteModel, CancellationToken>((model, _) => captured.Add(model))
+            .ReturnsAsync(ReadModelWithArea(1));
+
+        await NewService(data).ReconcileRosterAsync(7, new ReconcileVendorRosterDTO
+        {
+            RowVersion = "AAAAAAAAD8I=",
+            Name = "Acme Renamed",
+            Email = "acme@example.com",
+            AreaId = 1
+        }, "42", Dispatcher, CancellationToken.None);
+
+        await NewService(data).ReconcileRosterAsync(7, new ReconcileVendorRosterDTO
+        {
+            RowVersion = "AAAAAAAAD8I=",
+            Name = "Acme Renamed",
+            Email = "acme@example.com"
+        }, "42", Dispatcher, CancellationToken.None);
+
+        captured.Should().HaveCount(2);
+        captured[0].AreaIdProvided.Should().BeTrue();
+        captured[0].AreaId.Should().Be(1);
+        captured[1].AreaIdProvided.Should().BeFalse();
+    }
+
+    [Fact]
+    public async Task Reconcile_AdminClearsAreaToUnassigned()
+    {
+        var data = new Mock<IVendorCompanyRosterDataService>();
+        data.Setup(x => x.GetRosterAsync(null, 7, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(ReadModelWithArea(1));
+        VendorCompanyRosterWriteModel? captured = null;
+        data.Setup(x => x.SaveRosterAsync(It.IsAny<VendorCompanyRosterWriteModel>(), It.IsAny<CancellationToken>()))
+            .Callback<VendorCompanyRosterWriteModel, CancellationToken>((model, _) => captured = model)
+            .ReturnsAsync(ReadModelWithArea(null));
+
+        await NewService(data).ReconcileRosterAsync(7, new ReconcileVendorRosterDTO
+        {
+            RowVersion = "AAAAAAAAD8I=",
+            Name = "Acme",
+            Email = "acme@example.com",
+            AreaId = null
+        }, "42", Admin, CancellationToken.None);
+
+        captured!.AreaIdProvided.Should().BeTrue();
+        captured.AreaId.Should().BeNull();
+        data.Verify(x => x.IsActiveAreaAsync(It.IsAny<int>(), It.IsAny<CancellationToken>()), Times.Never);
+    }
+
+    [Fact]
+    public async Task AddTechnicians_NonAdminAreaChange_IsForbidden()
+    {
+        var data = new Mock<IVendorCompanyRosterDataService>();
+        data.Setup(x => x.GetRosterAsync(null, 7, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(ReadModelWithArea(null));
+        var dto = new AddTechniciansVendorRosterDTO
+        {
+            RowVersion = "AAAAAAAAD8I=",
+            CompanyFields = new VendorRosterCompanyFieldsDTO { AreaId = 2 }
+        };
+
+        var act = () => NewService(data).AddTechniciansAsync(7, dto, "42", Dispatcher, CancellationToken.None);
+
+        await act.Should().ThrowAsync<VendorAreaAssignmentForbiddenException>();
+        data.Verify(x => x.AddTechniciansAsync(It.IsAny<VendorCompanyRosterAddWriteModel>(), It.IsAny<CancellationToken>()), Times.Never);
+    }
+
+    [Fact]
+    public void ReconcileDto_DistinguishesOmittedAreaFromExplicitNull()
+    {
+        var omitted = System.Text.Json.JsonSerializer.Deserialize<ReconcileVendorRosterDTO>(
+            """{"rowVersion":"AAAAAAAAD8I=","name":"Acme"}""",
+            new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web))!;
+        var cleared = System.Text.Json.JsonSerializer.Deserialize<ReconcileVendorRosterDTO>(
+            """{"rowVersion":"AAAAAAAAD8I=","name":"Acme","areaId":null}""",
+            new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web))!;
+        var assigned = System.Text.Json.JsonSerializer.Deserialize<ReconcileVendorRosterDTO>(
+            """{"rowVersion":"AAAAAAAAD8I=","name":"Acme","areaId":3}""",
+            new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web))!;
+
+        omitted.AreaIdProvided.Should().BeFalse();
+        cleared.AreaIdProvided.Should().BeTrue();
+        cleared.AreaId.Should().BeNull();
+        assigned.AreaIdProvided.Should().BeTrue();
+        assigned.AreaId.Should().Be(3);
+    }
 }

Api.SeaHavenIndustries.Tests/VendorControllerTests.cs

@@ -72,6 +72,7 @@ public class VendorControllerTests
             It.IsAny<IReadOnlyCollection<string>?>(),
             It.IsAny<IReadOnlyCollection<string>?>(),
             It.IsAny<IReadOnlyCollection<string>?>(),
+            It.IsAny<IReadOnlyCollection<string>?>(),
             It.IsAny<CancellationToken>()), Times.Never);
     }
 
@@ -155,6 +156,7 @@ public class VendorControllerTests
                 It.IsAny<IReadOnlyCollection<string>?>(),
                 It.IsAny<IReadOnlyCollection<string>?>(),
                 It.IsAny<IReadOnlyCollection<string>?>(),
+                It.IsAny<IReadOnlyCollection<string>?>(),
                 token))
             .ReturnsAsync(new PagedResult<VendorDirectoryItemDTO>
             {
@@ -203,6 +205,7 @@ public class VendorControllerTests
             It.IsAny<IReadOnlyCollection<string>?>(),
             It.IsAny<IReadOnlyCollection<string>?>(),
             It.IsAny<IReadOnlyCollection<string>?>(),
+            It.IsAny<IReadOnlyCollection<string>?>(),
             token), Times.Once);
         service.Verify(x => x.GetVendorTechnicianDirectoryPagedAsync(
             It.IsAny<int>(),

Api.SeaHavenIndustries.Tests/VendorDataServiceTests.cs

@@ -470,12 +470,14 @@ public class VendorDataServiceTests
             search: "alice",
             trades: new[] { "Plumbing" },
             locations: new[] { "Chicago, IL" },
-            jobBuckets: new[] { "under-50" }).ToQueryString();
+            jobBuckets: new[] { "under-50" },
+            areaFilter: new VendorAreaFilter { AreaIds = new[] { 1, 2 }, IncludeUnassigned = true }).ToQueryString();
 
         sql.Should().Contain("GROUP BY");
         sql.Should().Contain("LEFT JOIN");
         sql.Should().Contain("TradeSpecialties");
         sql.Should().Contain("TotalJobs");
+        sql.Should().Contain("AreaId");
         Regex.IsMatch(sql, @"SUM\s*\(\s*\(\s*SELECT", RegexOptions.IgnoreCase)
             .Should().BeFalse("company totals must sum pre-aggregated scalar job counts");
     }
@@ -1044,4 +1046,69 @@ public class VendorDataServiceTests
         sql.Should().Contain("SELECT");
         sql.Should().Contain("VendorCompanies");
     }
+
+    [Fact]
+    public async Task GetCompanyDirectoryPagedAsync_AreaFilterOrsWithinFacetAndUnassignedIncludesLegacyRows()
+    {
+        await using var context = NewContext();
+        var east = new Area { Id = 1, Name = "East", NormalizedName = "east" };
+        var west = new Area { Id = 3, Name = "West", NormalizedName = "west" };
+        context.Areas.AddRange(east, west);
+        var eastCo = new VendorCompany { Name = "East Co", NormalizedName = "east co", Area = east };
+        var westCo = new VendorCompany { Name = "West Co", NormalizedName = "west co", Area = west };
+        var unassignedCo = new VendorCompany { Name = "Unassigned Co", NormalizedName = "unassigned co" };
+        var eastOnly = new VendorCompany { Name = "East Only", NormalizedName = "east only", Area = east };
+        context.VendorCompanies.AddRange(eastCo, westCo, unassignedCo, eastOnly);
+        context.Vendors.AddRange(
+            new Vendor { Company = eastCo, CompanyName = "East Co", ContactName = "E", City = "Boston", State = "MA", IsActive = true, IsDeleted = false },
+            new Vendor { Company = westCo, CompanyName = "West Co", ContactName = "W", IsActive = true, IsDeleted = false },
+            new Vendor { Company = unassignedCo, CompanyName = "Unassigned Co", ContactName = "U", IsActive = true, IsDeleted = false },
+            new Vendor { CompanyName = "Legacy Co", ContactName = "L", IsActive = true, IsDeleted = false });
+        await context.SaveChangesAsync();
+        var service = new VendorDataService(context);
+
+        var eastResult = await service.GetCompanyDirectoryPagedAsync(
+            1, 50, isActive: true, areaFilter: new VendorAreaFilter { AreaIds = new[] { east.Id } });
+        eastResult.Items.Select(item => item.CompanyName)
+            .Should().BeEquivalentTo("East Co", "East Only");
+        eastResult.TotalCount.Should().Be(2);
+        var eastRow = eastResult.Items.Single(item => item.CompanyName == "East Co");
+        eastRow.AreaId.Should().Be(east.Id);
+        eastRow.AreaName.Should().Be("East");
+        eastResult.Items.Single(item => item.CompanyName == "East Only").AreaName.Should().Be("East");
+
+        var eastOrUnassigned = await service.GetCompanyDirectoryPagedAsync(
+            1, 50, isActive: true,
+            areaFilter: new VendorAreaFilter { AreaIds = new[] { east.Id }, IncludeUnassigned = true });
+        eastOrUnassigned.Items.Select(item => item.CompanyName)
+            .Should().BeEquivalentTo("East Co", "East Only", "Unassigned Co", "Legacy Co");
+        eastOrUnassigned.Items.Single(item => item.CompanyName == "Legacy Co").AreaId.Should().BeNull();
+
+        var eastAndBoston = await service.GetCompanyDirectoryPagedAsync(
+            1, 50, isActive: true, locations: new[] { "Boston, MA" },
+            areaFilter: new VendorAreaFilter { AreaIds = new[] { east.Id } });
+        eastAndBoston.Items.Should().ContainSingle(item => item.CompanyName == "East Co");
+
+        var matchesNobody = await service.GetCompanyDirectoryPagedAsync(
+            1, 50, isActive: true, areaFilter: new VendorAreaFilter());
+        matchesNobody.TotalCount.Should().Be(0);
+        matchesNobody.Items.Should().BeEmpty();
+
+        var unfiltered = await service.GetCompanyDirectoryPagedAsync(1, 50, isActive: true);
+        unfiltered.TotalCount.Should().Be(5);
+    }
+
+    [Fact]
+    public async Task GetActiveAreasAsync_ExcludesArchivedAreas()
+    {
+        await using var context = NewContext();
+        context.Areas.AddRange(
+            new Area { Id = 1, Name = "East", NormalizedName = "east" },
+            new Area { Id = 4, Name = "California", NormalizedName = "california", IsActive = false });
+        await context.SaveChangesAsync();
+
+        var areas = await new VendorDataService(context).GetActiveAreasAsync(CancellationToken.None);
+
+        areas.Select(area => area.Name).Should().Equal("East");
+    }
 }

Api.SeaHavenIndustries.Tests/VendorServiceTests.cs

@@ -166,6 +166,7 @@ public class VendorServiceTests
                 It.IsAny<IReadOnlyCollection<string>?>(),
                 It.IsAny<IReadOnlyCollection<string>?>(),
                 It.IsAny<IReadOnlyCollection<string>?>(),
+                It.IsAny<VendorAreaFilter?>(),
                 token))
             .ReturnsAsync((new[]
             {
@@ -212,6 +213,7 @@ public class VendorServiceTests
             It.IsAny<IReadOnlyCollection<string>?>(),
             It.IsAny<IReadOnlyCollection<string>?>(),
             It.IsAny<IReadOnlyCollection<string>?>(),
+            It.IsAny<VendorAreaFilter?>(),
             token), Times.Once);
     }
 
@@ -228,6 +230,7 @@ public class VendorServiceTests
                 It.IsAny<IReadOnlyCollection<string>?>(),
                 It.IsAny<IReadOnlyCollection<string>?>(),
                 It.IsAny<IReadOnlyCollection<string>?>(),
+                It.IsAny<VendorAreaFilter?>(),
                 It.IsAny<CancellationToken>()))
             .ReturnsAsync((new List<VendorCompanyGroup>(), 0));
 
@@ -756,6 +759,8 @@ public class VendorServiceTests
             });
         data.Setup(x => x.GetActiveTradesAsync(It.IsAny<CancellationToken>()))
             .ReturnsAsync(new List<Trade>());
+        data.Setup(x => x.GetActiveAreasAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Area>());
 
         var facets = await NewService(data).GetFacetsAsync(true, CancellationToken.None);
 
@@ -794,6 +799,8 @@ public class VendorServiceTests
             });
         data.Setup(x => x.GetActiveTradesAsync(It.IsAny<CancellationToken>()))
             .ReturnsAsync(new List<Trade>());
+        data.Setup(x => x.GetActiveAreasAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Area>());
 
         var facets = await NewService(data).GetFacetsAsync(null, CancellationToken.None);
 
@@ -822,6 +829,8 @@ public class VendorServiceTests
             });
         data.Setup(x => x.GetActiveTradesAsync(It.IsAny<CancellationToken>()))
             .ReturnsAsync(new List<Trade>());
+        data.Setup(x => x.GetActiveAreasAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Area>());
 
         var facets = await NewService(data).GetFacetsAsync(null, CancellationToken.None);
 
@@ -849,6 +858,8 @@ public class VendorServiceTests
                     SortOrder = index + 1
                 })
                 .ToList());
+        data.Setup(x => x.GetActiveAreasAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Area>());
 
         var facets = await NewService(data).GetFacetsAsync(true, cts.Token);
 
@@ -898,4 +909,96 @@ public class VendorServiceTests
             TradeCatalog.CanonicalTrades,
             opts => opts.WithStrictOrdering());
     }
+
+    private static Mock<IVendorDataService> DirectoryDataWithAreas(Action<VendorAreaFilter?> capture)
+    {
+        var data = new Mock<IVendorDataService>();
+        data.Setup(x => x.GetActiveAreasAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Area>
+            {
+                new() { Id = 1, Name = "East", NormalizedName = "east" },
+                new() { Id = 3, Name = "West", NormalizedName = "west" }
+            });
+        data.Setup(x => x.GetCompanyDirectoryPagedAsync(
+                It.IsAny<int>(),
+                It.IsAny<int>(),
+                It.IsAny<string?>(),
+                It.IsAny<bool?>(),
+                It.IsAny<IReadOnlyCollection<string>?>(),
+                It.IsAny<IReadOnlyCollection<string>?>(),
+                It.IsAny<IReadOnlyCollection<string>?>(),
+                It.IsAny<IReadOnlyCollection<string>?>(),
+                It.IsAny<VendorAreaFilter?>(),
+                It.IsAny<CancellationToken>()))
+            .Callback<int, int, string?, bool?, IReadOnlyCollection<string>?, IReadOnlyCollection<string>?, IReadOnlyCollection<string>?, IReadOnlyCollection<string>?, VendorAreaFilter?, CancellationToken>(
+                (_, _, _, _, _, _, _, _, filter, _) => capture(filter))
+            .ReturnsAsync((new List<VendorCompanyGroup>(), 0));
+        return data;
+    }
+
+    [Fact]
+    public async Task GetVendorCompanyDirectoryPaged_ResolvesAreaIdsAndUnassignedSentinel()
+    {
+        VendorAreaFilter? captured = null;
+        var data = DirectoryDataWithAreas(filter => captured = filter);
+
+        await NewService(data).GetVendorCompanyDirectoryPagedAsync(
+            1, 10, areas: new[] { " 1 ", "__unassigned__", "", "1" });
+
+        captured.Should().NotBeNull();
+        captured!.AreaIds.Should().Equal(1);
+        captured.IncludeUnassigned.Should().BeTrue();
+    }
+
+    [Fact]
+    public async Task GetVendorCompanyDirectoryPaged_UnknownArchivedOrLabelAreaValuesMatchNobody()
+    {
+        VendorAreaFilter? captured = null;
+        var data = DirectoryDataWithAreas(filter => captured = filter);
+
+        // 4 is not in the active catalogue (unknown or archived); "West" is a label.
+        var result = await NewService(data).GetVendorCompanyDirectoryPagedAsync(
+            1, 10, areas: new[] { "4", "West", "-3" });
+
+        captured.Should().NotBeNull();
+        captured!.AreaIds.Should().BeEmpty();
+        captured.IncludeUnassigned.Should().BeFalse();
+        result.Items.Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task GetVendorCompanyDirectoryPaged_BlankAreaValuesApplyNoAreaFilter()
+    {
+        VendorAreaFilter? captured = new();
+        var data = DirectoryDataWithAreas(filter => captured = filter);
+
+        await NewService(data).GetVendorCompanyDirectoryPagedAsync(1, 10, areas: new[] { " ", "" });
+
+        captured.Should().BeNull();
+        data.Verify(x => x.GetActiveAreasAsync(It.IsAny<CancellationToken>()), Times.Never);
+    }
+
+    [Fact]
+    public async Task GetFacetsAsync_AreasComeFromActiveCatalogueOrderedByName()
+    {
+        using var cts = new CancellationTokenSource();
+        var data = new Mock<IVendorDataService>();
+        data.Setup(x => x.GetCompaniesForFacetsAsync(null, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<VendorCompany>());
+        data.Setup(x => x.GetActiveTradesAsync(It.IsAny<CancellationToken>()))
+            .ReturnsAsync(new List<Trade>());
+        data.Setup(x => x.GetActiveAreasAsync(cts.Token))
+            .ReturnsAsync(new List<Area>
+            {
+                new() { Id = 3, Name = "West", NormalizedName = "west" },
+                new() { Id = 1, Name = "East", NormalizedName = "east" },
+                new() { Id = 4, Name = "california", NormalizedName = "california" }
+            });
+
+        var facets = await NewService(data).GetFacetsAsync(null, cts.Token);
+
+        facets.Areas.Select(area => (area.Id, area.Name)).Should().Equal(
+            (4, "california"), (1, "East"), (3, "West"));
+        data.Verify(x => x.GetActiveAreasAsync(cts.Token), Times.Once);
+    }
 }

Api.SeaHavenIndustries/Controllers/VendorCompanyRosterController.cs

@@ -2,6 +2,7 @@ using Api.SeaHavenIndustries.Helper;
 using Data.SeaHavenIndustries;
 using FluentValidation;
 using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
@@ -70,7 +71,7 @@ namespace Api.SeaHavenIndustries.Controllers
 
             try
             {
-                var roster = await _rosterService.CreateRosterAsync(model, userId, cancellationToken);
+                var roster = await _rosterService.CreateRosterAsync(model, userId, User, cancellationToken);
                 return Ok(roster);
             }
             catch (ValidationException vex)
@@ -82,6 +83,12 @@ namespace Api.SeaHavenIndustries.Controllers
             {
                 return Unauthorized(new Response { Status = "Error", Message = "User not authenticated" });
             }
+            catch (VendorAreaAssignmentForbiddenException)
+            {
+                return StatusCode(
+                    StatusCodes.Status403Forbidden,
+                    new Response { Status = "Error", Message = "Only administrators can assign a vendor company Area." });
+            }
             catch (VendorRosterDuplicateNameException dup)
             {
                 return Conflict(new
@@ -109,7 +116,7 @@ namespace Api.SeaHavenIndustries.Controllers
 
             try
             {
-                var roster = await _rosterService.ReconcileRosterAsync(companyId, model, userId, cancellationToken);
+                var roster = await _rosterService.ReconcileRosterAsync(companyId, model, userId, User, cancellationToken);
                 return Ok(roster);
             }
             catch (ValidationException vex)
@@ -121,6 +128,12 @@ namespace Api.SeaHavenIndustries.Controllers
             {
                 return Unauthorized(new Response { Status = "Error", Message = "User not authenticated" });
             }
+            catch (VendorAreaAssignmentForbiddenException)
+            {
+                return StatusCode(
+                    StatusCodes.Status403Forbidden,
+                    new Response { Status = "Error", Message = "Only administrators can assign a vendor company Area." });
+            }
             catch (KeyNotFoundException)
             {
                 return NotFound(new Response { Status = "Error", Message = "Vendor company not found" });
@@ -164,7 +177,7 @@ namespace Api.SeaHavenIndustries.Controllers
 
             try
             {
-                var roster = await _rosterService.AddTechniciansAsync(companyId, model, userId, cancellationToken);
+                var roster = await _rosterService.AddTechniciansAsync(companyId, model, userId, User, cancellationToken);
                 return Ok(roster);
             }
             catch (ValidationException vex)
@@ -176,6 +189,12 @@ namespace Api.SeaHavenIndustries.Controllers
             {
                 return Unauthorized(new Response { Status = "Error", Message = "User not authenticated" });
             }
+            catch (VendorAreaAssignmentForbiddenException)
+            {
+                return StatusCode(
+                    StatusCodes.Status403Forbidden,
+                    new Response { Status = "Error", Message = "Only administrators can assign a vendor company Area." });
+            }
             catch (KeyNotFoundException)
             {
                 return NotFound(new Response { Status = "Error", Message = "Vendor company not found" });

Api.SeaHavenIndustries/Controllers/VendorController.cs

@@ -97,6 +97,7 @@ namespace Api.SeaHavenIndustries.Controllers
             [FromQuery] string[]? trades = null,
             [FromQuery] string[]? locations = null,
             [FromQuery] string[]? jobBuckets = null,
+            [FromQuery] string[]? areas = null,
             CancellationToken cancellationToken = default)
         {
             var pagedResult = await _vendorService.GetVendorCompanyDirectoryPagedAsync(
@@ -108,6 +109,7 @@ namespace Api.SeaHavenIndustries.Controllers
                 trades,
                 locations,
                 jobBuckets,
+                areas,
                 cancellationToken);
 
             var data = pagedResult.Items.Select(v => new
@@ -129,6 +131,8 @@ namespace Api.SeaHavenIndustries.Controllers
                 v.Notes,
                 v.IsActive,
                 v.TotalJobs,
+                v.AreaId,
+                v.AreaName,
                 Technicians = v.Technicians.Select(t => new
                 {
                     t.Id,

Data.SeaHavenIndustries/Auth/ApplicationDbContext.cs

@@ -206,6 +206,25 @@ namespace Data.SeaHavenIndustries
             builder.Entity<Trade>()
                 .HasIndex(t => t.NormalizedName)
                 .IsUnique();
+
+            // SH-278 Area catalogue: bounded names so the unique key is indexable.
+            builder.Entity<Area>()
+                .Property(a => a.Name)
+                .HasMaxLength(128);
+
+            builder.Entity<Area>()
+                .Property(a => a.NormalizedName)
+                .HasMaxLength(128);
+
+            builder.Entity<Area>()
+                .HasIndex(a => a.NormalizedName)
+                .IsUnique();
+
+            builder.Entity<VendorCompany>()
+                .HasOne(c => c.Area)
+                .WithMany()
+                .HasForeignKey(c => c.AreaId)
+                .OnDelete(DeleteBehavior.Restrict);
         }
         public DbSet<Category> Categories { get; set; }
         public DbSet<Locations> Locations { get; set; }
@@ -228,6 +247,7 @@ namespace Data.SeaHavenIndustries
         public DbSet<WorkOrderExternalReceipt> WorkOrderExternalReceipts { get; set; }
         public DbSet<DropdownOption> DropdownOptions { get; set; }
         public DbSet<Trade> Trades { get; set; }
+        public DbSet<Area> Areas { get; set; }
         public DbSet<Vendor> Vendors { get; set; }
         public DbSet<VendorCompany> VendorCompanies { get; set; }
         public DbSet<VendorAuditLog> VendorAuditLogs { get; set; }

Data.SeaHavenIndustries/Migrations/20260916140128_SH278_VendorCompanyArea.cs

@@ -0,0 +1,88 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Data.SeaHavenIndustries.Migrations
+{
+    /// <inheritdoc />
+    public partial class SH278_VendorCompanyArea : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<int>(
+                name: "AreaId",
+                table: "VendorCompanies",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.CreateTable(
+                name: "Areas",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "int", nullable: false)
+                        .Annotation("SqlServer:Identity", "1, 1"),
+                    Name = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: false),
+                    NormalizedName = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: false),
+                    IsActive = table.Column<bool>(type: "bit", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Areas", x => x.Id);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_VendorCompanies_AreaId",
+                table: "VendorCompanies",
+                column: "AreaId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Areas_NormalizedName",
+                table: "Areas",
+                column: "NormalizedName",
+                unique: true);
+
+            // SH-278 v1 seed of the four dispatcher territories confirmed by Product.
+            // Names match the merged SH-273 Sites mapping (East / Central / West /
+            // California). Ids are stable; later renames change only the display name.
+            // Existing vendor companies stay Unassigned (no backfill).
+            migrationBuilder.InsertData(
+                table: "Areas",
+                columns: new[] { "Id", "Name", "NormalizedName", "IsActive" },
+                values: new object[,]
+                {
+                    { 1, "East", "east", true },
+                    { 2, "Central", "central", true },
+                    { 3, "West", "west", true },
+                    { 4, "California", "california", true }
+                });
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_VendorCompanies_Areas_AreaId",
+                table: "VendorCompanies",
+                column: "AreaId",
+                principalTable: "Areas",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_VendorCompanies_Areas_AreaId",
+                table: "VendorCompanies");
+
+            migrationBuilder.DropTable(
+                name: "Areas");
+
+            migrationBuilder.DropIndex(
+                name: "IX_VendorCompanies_AreaId",
+                table: "VendorCompanies");
+
+            migrationBuilder.DropColumn(
+                name: "AreaId",
+                table: "VendorCompanies");
+        }
+    }
+}

Data.SeaHavenIndustries/Migrations/ApplicationDbContextModelSnapshot.cs

@@ -286,6 +286,35 @@ namespace Data.SeaHavenIndustries.Migrations
                     b.ToTable("AspNetUsers", (string)null);
                 });
 
+            modelBuilder.Entity("Data.SeaHavenIndustries.Area", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("int");
+
+                    SqlServerPropertyBuilderExtensions.UseIdentityColumn(b.Property<int>("Id"));
+
+                    b.Property<bool>("IsActive")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.Property<string>("NormalizedName")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("NormalizedName")
+                        .IsUnique();
+
+                    b.ToTable("Areas");
+                });
+
             modelBuilder.Entity("Data.SeaHavenIndustries.Assets", b =>
                 {
                     b.Property<int>("Id")
@@ -2237,6 +2266,9 @@ namespace Data.SeaHavenIndustries.Migrations
                     b.Property<string>("Address")
                         .HasColumnType("nvarchar(max)");
 
+                    b.Property<int?>("AreaId")
+                        .HasColumnType("int");
+
                     b.Property<string>("City")
                         .HasColumnType("nvarchar(max)");
 
@@ -2294,6 +2326,8 @@ namespace Data.SeaHavenIndustries.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("AreaId");
+
                     b.HasIndex("NormalizedName")
                         .IsUnique();
 
@@ -3614,6 +3648,16 @@ namespace Data.SeaHavenIndustries.Migrations
                     b.Navigation("Vendor");
                 });
 
+            modelBuilder.Entity("Data.SeaHavenIndustries.VendorCompany", b =>
+                {
+                    b.HasOne("Data.SeaHavenIndustries.Area", "Area")
+                        .WithMany()
+                        .HasForeignKey("AreaId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
+                    b.Navigation("Area");
+                });
+
             modelBuilder.Entity("Data.SeaHavenIndustries.VendorCompletionDocument", b =>
                 {
                     b.HasOne("Data.SeaHavenIndustries.Dispatch", "Dispatch")

Data.SeaHavenIndustries/Models/Area.cs

@@ -0,0 +1,15 @@
+namespace Data.SeaHavenIndustries
+{
+    // SH-278: dispatcher territory catalogue for this Sea Haven deployment. Vendor
+    // companies carry zero or one Area by stable id; the display name is separate and
+    // may be renamed without changing assignments. Area is selected independently and
+    // is never derived from a company's State. Rows are organization-wide: vendor
+    // companies are not scoped to a customer Account.
+    public class Area
+    {
+        public int Id { get; set; }
+        public string Name { get; set; } = "";
+        public string NormalizedName { get; set; } = "";
+        public bool IsActive { get; set; } = true;
+    }
+}

Data.SeaHavenIndustries/Models/VendorCompany.cs

@@ -16,6 +16,11 @@ namespace Data.SeaHavenIndustries
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
 
+        // SH-278: optional dispatcher territory (0 or 1 per company), admin-assigned.
+        public int? AreaId { get; set; }
+        [ForeignKey(nameof(AreaId))]
+        public Area? Area { get; set; }
+
         [Timestamp]
         public byte[]? RowVersion { get; set; }
 

SeaHaven.DataServices/Implementation/VendorCompanyRosterDataService.cs

@@ -17,6 +17,11 @@ namespace SeaHaven.DataServices.Implementation
             _context = context;
         }
 
+        public Task<bool> IsActiveAreaAsync(int areaId, CancellationToken cancellationToken) =>
+            _context.Areas
+                .AsNoTracking()
+                .AnyAsync(area => area.Id == areaId && area.IsActive, cancellationToken);
+
         public async Task<VendorCompanyRosterReadModel?> GetRosterAsync(
             int? vendorId,
             int? companyId,
@@ -57,6 +62,8 @@ namespace SeaHaven.DataServices.Implementation
                     Zip = c.Zip,
                     GoogleMapsUrl = c.GoogleMapsUrl,
                     Notes = c.Notes,
+                    AreaId = c.AreaId,
+                    AreaName = c.Area != null ? c.Area.Name : null,
                     RowVersion = c.RowVersion
                 })
                 .FirstOrDefaultAsync(cancellationToken);
@@ -114,6 +121,8 @@ namespace SeaHaven.DataServices.Implementation
             company.Zip = roster.Zip;
             company.GoogleMapsUrl = roster.GoogleMapsUrl;
             company.Notes = roster.Notes;
+            if (roster.AreaIdProvided)
+                company.AreaId = roster.AreaId;
             company.LastModificationTime = now;
             int? actorId = int.TryParse(roster.ActorUserId, out var parsedActorId) ? parsedActorId : null;
             if (actorId.HasValue)
@@ -245,6 +254,7 @@ namespace SeaHaven.DataServices.Implementation
                 Zip = roster.Zip,
                 GoogleMapsUrl = roster.GoogleMapsUrl,
                 Notes = roster.Notes,
+                AreaId = roster.AreaId,
                 CreatedDate = now,
                 createdby = roster.ActorUserId
             };
@@ -367,6 +377,8 @@ namespace SeaHaven.DataServices.Implementation
                     company.GoogleMapsUrl = fields.GoogleMapsUrl;
                 if (fields.Notes != null)
                     company.Notes = fields.Notes;
+                if (fields.AreaIdProvided)
+                    company.AreaId = fields.AreaId;
 
                 // Keep the denormalized company columns on existing technicians aligned
                 // with the company row (same invariant SaveRosterAsync maintains). This

SeaHaven.DataServices/Implementation/VendorDataService.cs

@@ -106,6 +106,15 @@ namespace SeaHaven.DataServices.Implementation
             return query.OrderBy(c => c.Id);
         }
 
+        public async Task<IReadOnlyList<Area>> GetActiveAreasAsync(CancellationToken cancellationToken)
+        {
+            return await _context.Areas
+                .AsNoTracking()
+                .Where(a => a.IsActive)
+                .OrderBy(a => a.Id)
+                .ToListAsync(cancellationToken);
+        }
+
         public async Task<IReadOnlyList<VendorCompany>> GetCompaniesForFacetsAsync(bool? isActive, CancellationToken cancellationToken)
             => await BuildCompaniesForFacetsQuery(isActive).ToListAsync(cancellationToken);
 
@@ -177,6 +186,7 @@ namespace SeaHaven.DataServices.Implementation
             IReadOnlyCollection<string>? trades = null,
             IReadOnlyCollection<string>? locations = null,
             IReadOnlyCollection<string>? jobBuckets = null,
+            VendorAreaFilter? areaFilter = null,
             CancellationToken cancellationToken = default)
         {
             // Phase 1: select and paginate bounded company group keys in SQL.
@@ -186,7 +196,8 @@ namespace SeaHaven.DataServices.Implementation
                 companies,
                 trades,
                 locations,
-                jobBuckets);
+                jobBuckets,
+                areaFilter);
 
             var totalCount = await keyQuery.CountAsync(cancellationToken);
 
@@ -222,6 +233,7 @@ namespace SeaHaven.DataServices.Implementation
                 ? new Dictionary<int, VendorCompany>()
                 : await _context.VendorCompanies
                     .AsNoTracking()
+                    .Include(c => c.Area)
                     .Where(c => missingCompanyIds.Contains(c.Id))
                     .ToDictionaryAsync(c => c.Id, cancellationToken);
 
@@ -291,6 +303,8 @@ namespace SeaHaven.DataServices.Implementation
                 TradeSpecialties = AggregateTradeTokens(techniciansNewestFirst),
                 GoogleMapsUrl = primary.GoogleMapsUrl,
                 Notes = linked ? primary.CompanyNotes : null,
+                AreaId = linked ? primary.CompanyAreaId : null,
+                AreaName = linked ? primary.CompanyAreaName : null,
                 IsActive = primary.IsActive,
                 TotalJobs = techniciansNewestFirst.Sum(row => row.TotalJobs),
                 Technicians = techniciansNewestFirst.Select(row => new VendorCompanyGroupTechnician
@@ -344,6 +358,8 @@ namespace SeaHaven.DataServices.Implementation
             TradeSpecialties = null,
             GoogleMapsUrl = company.GoogleMapsUrl,
             Notes = company.Notes,
+            AreaId = company.AreaId,
+            AreaName = company.Area?.Name,
             IsActive = true,
             TotalJobs = 0,
             Technicians = Array.Empty<VendorCompanyGroupTechnician>()
@@ -355,10 +371,11 @@ namespace SeaHaven.DataServices.Implementation
             IReadOnlyCollection<string>? companies = null,
             IReadOnlyCollection<string>? trades = null,
             IReadOnlyCollection<string>? locations = null,
-            IReadOnlyCollection<string>? jobBuckets = null)
+            IReadOnlyCollection<string>? jobBuckets = null,
+            VendorAreaFilter? areaFilter = null)
         {
             var sourceRows = BuildDirectoryUnionBaseQuery(isActive)
-                .Select(BuildGroupSourceRowSelector(search, companies, trades, locations));
+                .Select(BuildGroupSourceRowSelector(search, companies, trades, locations, areaFilter));
 
             var grouped = sourceRows
                 .GroupBy(row => new { row.CompanyId, row.NameKey, row.VendorKey })
@@ -372,7 +389,8 @@ namespace SeaHaven.DataServices.Implementation
                     SearchMatch = group.Max(row => row.SearchFlag),
                     CompanyMatch = group.Max(row => row.CompanyFlag),
                     TradeMatch = group.Max(row => row.TradeFlag),
-                    LocationMatch = group.Max(row => row.LocationFlag)
+                    LocationMatch = group.Max(row => row.LocationFlag),
+                    AreaMatch = group.Max(row => row.AreaFlag)
                 });
 
             // Each facet selects the group when any status-eligible row matches it
@@ -405,6 +423,9 @@ namespace SeaHaven.DataServices.Implementation
             if (selectedLocations is { Length: > 0 })
                 grouped = grouped.Where(key => key.LocationMatch == 1);
 
+            if (areaFilter != null)
+                grouped = grouped.Where(key => key.AreaMatch == 1);
+
             var selectedJobBuckets = jobBuckets?
                 .Where(value => !string.IsNullOrWhiteSpace(value))
                 .Select(value => value.Trim().ToLower())
@@ -429,7 +450,8 @@ namespace SeaHaven.DataServices.Implementation
             string? search,
             IReadOnlyCollection<string>? companies,
             IReadOnlyCollection<string>? trades,
-            IReadOnlyCollection<string>? locations)
+            IReadOnlyCollection<string>? locations,
+            VendorAreaFilter? areaFilter)
         {
             var row = Expression.Parameter(typeof(VendorDirectoryRow), "row");
 
@@ -466,6 +488,9 @@ namespace SeaHaven.DataServices.Implementation
             var locationBody = selectedLocations is { Length: > 0 }
                 ? BuildLocationMatchBody<VendorDirectoryRow>(row, selectedLocations)
                 : null;
+            var areaBody = areaFilter == null
+                ? null
+                : BuildAreaMatchBody(row, areaFilter);
 
             var nameKey = Expression.Condition(
                 Expression.NotEqual(
@@ -508,7 +533,8 @@ namespace SeaHaven.DataServices.Implementation
                     Bind(nameof(VendorDirectoryGroupSourceRow.SearchFlag), Flag(searchBody)),
                     Bind(nameof(VendorDirectoryGroupSourceRow.CompanyFlag), Flag(companyBody)),
                     Bind(nameof(VendorDirectoryGroupSourceRow.TradeFlag), Flag(tradeBody)),
-                    Bind(nameof(VendorDirectoryGroupSourceRow.LocationFlag), Flag(locationBody))),
+                    Bind(nameof(VendorDirectoryGroupSourceRow.LocationFlag), Flag(locationBody)),
+                    Bind(nameof(VendorDirectoryGroupSourceRow.AreaFlag), Flag(areaBody))),
                 row);
         }
 
@@ -535,6 +561,8 @@ namespace SeaHaven.DataServices.Implementation
                 CompanyCity = v.Company != null ? v.Company.City : null,
                 CompanyState = v.Company != null ? v.Company.State : null,
                 CompanyNotes = v.Company != null ? v.Company.Notes : null,
+                CompanyAreaId = v.Company != null ? v.Company.AreaId : null,
+                CompanyAreaName = v.Company != null && v.Company.Area != null ? v.Company.Area.Name : null,
                 ContactName = v.ContactName,
                 Email = v.Email,
                 Phone = v.Phone,
@@ -702,6 +730,7 @@ namespace SeaHaven.DataServices.Implementation
                     TradeSpecialties = v.TradeSpecialties,
                     GoogleMapsUrl = v.GoogleMapsUrl,
                     Notes = v.Company != null ? v.Company.Notes : null,
+                    AreaId = v.Company != null ? v.Company.AreaId : null,
                     IsActive = v.IsActive,
                     TotalJobs = (int?)jobCount.TotalJobs ?? 0
                 };
@@ -736,6 +765,7 @@ namespace SeaHaven.DataServices.Implementation
                         TradeSpecialties = null,
                         GoogleMapsUrl = c.GoogleMapsUrl,
                         Notes = c.Notes,
+                        AreaId = c.AreaId,
                         IsActive = true,
                         TotalJobs = 0
                     });
@@ -777,6 +807,32 @@ namespace SeaHaven.DataServices.Implementation
             return body!;
         }
 
+        // SH-278: OR within the Area facet. Selected ids match the company's stable
+        // AreaId; the Unassigned sentinel matches rows without an Area, which includes
+        // unlinked legacy vendors that have no VendorCompany at all. A filter with no
+        // resolvable ids and no Unassigned matches nobody.
+        private static Expression BuildAreaMatchBody(ParameterExpression row, VendorAreaFilter areaFilter)
+        {
+            var areaId = Expression.Property(row, nameof(VendorDirectoryRow.AreaId));
+            Expression? body = null;
+
+            if (areaFilter.AreaIds.Count > 0)
+            {
+                var ids = areaFilter.AreaIds.Distinct().Select(id => (int?)id).ToArray();
+                body = OrElse(body, Expression.Call(
+                    typeof(Enumerable),
+                    nameof(Enumerable.Contains),
+                    new[] { typeof(int?) },
+                    Expression.Constant(ids),
+                    areaId));
+            }
+
+            if (areaFilter.IncludeUnassigned)
+                body = OrElse(body, Expression.Equal(areaId, Expression.Constant(null, typeof(int?))));
+
+            return body ?? Expression.Constant(false);
+        }
+
         private static Expression BuildCompanyNameMatchBody(
             ParameterExpression row,
             IReadOnlyCollection<string> selectedCompanies)

SeaHaven.DataServices/Interfaces/IVendorCompanyRosterDataService.cs

@@ -4,6 +4,9 @@ namespace SeaHaven.DataServices.Interfaces
 {
     public interface IVendorCompanyRosterDataService
     {
+        // SH-278: true only for an existing, non-archived Area in the catalogue.
+        Task<bool> IsActiveAreaAsync(int areaId, CancellationToken cancellationToken);
+
         // Loads the company roster from either a vendor row id and/or a company id,
         // returning the company plus all non-deleted technician rows.
         Task<VendorCompanyRosterReadModel?> GetRosterAsync(

SeaHaven.DataServices/Interfaces/IVendorDataService.cs

@@ -19,6 +19,10 @@ namespace SeaHaven.DataServices.Interfaces
         // of technician Vendor.TradeSpecialties free text.
         Task<IReadOnlyList<Trade>> GetActiveTradesAsync(CancellationToken cancellationToken);
 
+        // SH-278: active (non-archived) Area catalogue rows for vendor facets and for
+        // resolving areas[n] filter ids. Archived Areas are excluded.
+        Task<IReadOnlyList<Area>> GetActiveAreasAsync(CancellationToken cancellationToken);
+
         // SH-198 facet fix: company-owned facet profiles sourced from VendorCompanies,
         // with status semantics aligned to BuildDirectoryUnionQuery. Null returns all
         // companies; active includes companies with zero non-deleted technicians or at
@@ -66,6 +70,7 @@ namespace SeaHaven.DataServices.Interfaces
             IReadOnlyCollection<string>? trades = null,
             IReadOnlyCollection<string>? locations = null,
             IReadOnlyCollection<string>? jobBuckets = null,
+            VendorAreaFilter? areaFilter = null,
             CancellationToken cancellationToken = default);
         Task<Vendor> AddAsync(Vendor vendor);
         Task UpdateAsync(Vendor vendor);

SeaHaven.DataServices/Models/VendorCompanyRosterModels.cs

@@ -14,6 +14,8 @@ namespace SeaHaven.DataServices.Models
         public string? Zip { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+        public int? AreaId { get; set; }
+        public string? AreaName { get; set; }
         public byte[]? RowVersion { get; set; }
         public List<VendorRosterTechnicianReadModel> Technicians { get; set; } = new();
     }
@@ -43,6 +45,10 @@ namespace SeaHaven.DataServices.Models
         public string? Zip { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+
+        // SH-278: applied only when AreaIdProvided; null AreaId means Unassigned.
+        public bool AreaIdProvided { get; set; }
+        public int? AreaId { get; set; }
         public string? ActorUserId { get; set; }
         public List<RosterTechnicianWriteModel> Technicians { get; set; } = new();
     }
@@ -81,6 +87,10 @@ namespace SeaHaven.DataServices.Models
         public string? Zip { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+
+        // SH-278: applied only when AreaIdProvided; null AreaId means Unassigned.
+        public bool AreaIdProvided { get; set; }
+        public int? AreaId { get; set; }
     }
 
     // Raised by the roster data service when a technician removed from the snapshot

SeaHaven.DataServices/Models/VendorDirectoryReadModels.cs

@@ -17,10 +17,20 @@ namespace SeaHaven.DataServices.Models
         public string? TradeSpecialties { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+        public int? AreaId { get; set; }
         public bool IsActive { get; set; }
         public int TotalJobs { get; set; }
     }
 
+    // SH-278: Area facet filter for the company directory. AreaIds are already
+    // resolved against the active catalogue; IncludeUnassigned selects groups with no
+    // Area (including unlinked legacy vendors). An empty filter matches nobody.
+    public sealed class VendorAreaFilter
+    {
+        public IReadOnlyCollection<int> AreaIds { get; init; } = Array.Empty<int>();
+        public bool IncludeUnassigned { get; init; }
+    }
+
     // SH-281 company directory: per-row source for the grouped key query. Carries the
     // company group key parts (CompanyId 0 = unlinked; NameKey groups unlinked legacy
     // vendors by trimmed case-insensitive CompanyName; VendorKey isolates vendors with
@@ -37,6 +47,7 @@ namespace SeaHaven.DataServices.Models
         public int CompanyFlag { get; set; }
         public int TradeFlag { get; set; }
         public int LocationFlag { get; set; }
+        public int AreaFlag { get; set; }
     }
 
     // SH-281: one row per company group after SQL grouping — the bounded key page.
@@ -51,6 +62,7 @@ namespace SeaHaven.DataServices.Models
         public int CompanyMatch { get; set; }
         public int TradeMatch { get; set; }
         public int LocationMatch { get; set; }
+        public int AreaMatch { get; set; }
     }
 
     // SH-281: full status-eligible roster row (phase 2) carrying both the vendor's own
@@ -69,6 +81,8 @@ namespace SeaHaven.DataServices.Models
         public string? CompanyCity { get; set; }
         public string? CompanyState { get; set; }
         public string? CompanyNotes { get; set; }
+        public int? CompanyAreaId { get; set; }
+        public string? CompanyAreaName { get; set; }
         public string? ContactName { get; set; }
         public string? Email { get; set; }
         public string? Phone { get; set; }
@@ -124,6 +138,8 @@ namespace SeaHaven.DataServices.Models
         public string? TradeSpecialties { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+        public int? AreaId { get; set; }
+        public string? AreaName { get; set; }
         public bool IsActive { get; set; }
         public int TotalJobs { get; set; }
         public IReadOnlyList<VendorCompanyGroupTechnician> Technicians { get; set; } = Array.Empty<VendorCompanyGroupTechnician>();

SeaHaven.Services/DTOs/VendorCompanyRosterDTOs.cs

@@ -1,3 +1,5 @@
+using System.Text.Json.Serialization;
+
 namespace SeaHaven.Services.DTOs
 {
     public class VendorRosterDTO
@@ -12,6 +14,8 @@ namespace SeaHaven.Services.DTOs
         public string? Zip { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+        public int? AreaId { get; set; }
+        public string? AreaName { get; set; }
         public string? RowVersion { get; set; }
         public List<VendorRosterTechnicianDTO> Technicians { get; set; } = new();
     }
@@ -50,6 +54,10 @@ namespace SeaHaven.Services.DTOs
         public string? Zip { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+
+        // SH-278: optional Area id; null leaves the new company Unassigned. Assigning
+        // an Area requires the Admin role.
+        public int? AreaId { get; set; }
         public List<RosterTechnicianInputDTO> Technicians { get; set; } = new();
     }
 
@@ -65,6 +73,22 @@ namespace SeaHaven.Services.DTOs
         public string? Zip { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+
+        // SH-278: an omitted areaId leaves the stored Area unchanged, so clients that
+        // predate Area never clear it. An explicit null clears it to Unassigned.
+        private int? _areaId;
+        public int? AreaId
+        {
+            get => _areaId;
+            set
+            {
+                _areaId = value;
+                AreaIdProvided = true;
+            }
+        }
+
+        [JsonIgnore]
+        public bool AreaIdProvided { get; private set; }
         public List<RosterTechnicianInputDTO> Technicians { get; set; } = new();
     }
 
@@ -89,5 +113,30 @@ namespace SeaHaven.Services.DTOs
         public string? Zip { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+
+        // SH-278: same presence semantics as ReconcileVendorRosterDTO.AreaId.
+        private int? _areaId;
+        public int? AreaId
+        {
+            get => _areaId;
+            set
+            {
+                _areaId = value;
+                AreaIdProvided = true;
+            }
+        }
+
+        [JsonIgnore]
+        public bool AreaIdProvided { get; private set; }
+    }
+
+    // SH-278: raised when a caller without the Admin role tries to change a vendor
+    // company's Area. Mapped to a stable 403 by the API.
+    public sealed class VendorAreaAssignmentForbiddenException : Exception
+    {
+        public VendorAreaAssignmentForbiddenException()
+            : base("Only administrators can assign a vendor company Area.")
+        {
+        }
     }
 }

SeaHaven.Services/DTOs/VendorDTOs.cs

@@ -45,6 +45,8 @@ namespace SeaHaven.Services.DTOs
         public string? TradeSpecialties { get; set; }
         public string? GoogleMapsUrl { get; set; }
         public string? Notes { get; set; }
+        public int? AreaId { get; set; }
+        public string? AreaName { get; set; }
         public int TotalJobs { get; set; }
         public bool IsActive { get; set; }
         public List<VendorDirectoryTechnicianDTO> Technicians { get; set; } = new();

SeaHaven.Services/DTOs/VendorPortalDTOs.cs

@@ -59,7 +59,21 @@ namespace SeaHaven.Services.DTOs
     {
         public IEnumerable<VendorFacetCompanyDTO> Companies { get; set; } = Enumerable.Empty<VendorFacetCompanyDTO>();
         public IEnumerable<string> Trades { get; set; } = Enumerable.Empty<string>();
+        public IEnumerable<VendorFacetAreaDTO> Areas { get; set; } = Enumerable.Empty<VendorFacetAreaDTO>();
         public IEnumerable<VendorFacetLocationDTO> Locations { get; set; } = Enumerable.Empty<VendorFacetLocationDTO>();
         public IEnumerable<VendorJobBucketDTO> JobBuckets { get; set; } = Enumerable.Empty<VendorJobBucketDTO>();
     }
+
+    // SH-278: one active Area option. Id is the stable areas[n] filter value.
+    public class VendorFacetAreaDTO
+    {
+        public int Id { get; set; }
+        public string Name { get; set; } = string.Empty;
+    }
+
+    // SH-278: wire values accepted by the vendor directory areas[n] filter besides ids.
+    public static class VendorAreaFilterValues
+    {
+        public const string Unassigned = "__unassigned__";
+    }
 }

SeaHaven.Services/Implementation/VendorCompanyRosterService.cs

@@ -6,6 +6,7 @@ using SeaHaven.Services.DTOs;
 using SeaHaven.Services.Helpers;
 using SeaHaven.Services.Interfaces;
 using SeaHaven.Services.Validation;
+using System.Security.Claims;
 
 namespace SeaHaven.Services.Implementation
 {
@@ -13,6 +14,8 @@ namespace SeaHaven.Services.Implementation
     {
         private const int MaxNotesLength = 500;
         private const string NotesMaxLengthMessage = "Notes cannot exceed 500 characters.";
+        private const string AdminRole = "Admin";
+        private const string AreaNotFoundMessage = "Area was not found.";
 
         private readonly IVendorCompanyRosterDataService _rosterDataService;
 
@@ -39,6 +42,7 @@ namespace SeaHaven.Services.Implementation
         public async Task<VendorRosterDTO> CreateRosterAsync(
             CreateVendorRosterDTO dto,
             string userId,
+            ClaimsPrincipal caller,
             CancellationToken cancellationToken)
         {
             EnsureAuthenticated(userId);
@@ -60,6 +64,13 @@ namespace SeaHaven.Services.Implementation
                         "Technician ids are not allowed when creating a vendor company.")
                 });
 
+            await EnsureAreaAssignmentAllowedAsync(
+                caller,
+                dto.AreaId,
+                currentAreaId: null,
+                nameof(CreateVendorRosterDTO.AreaId),
+                cancellationToken);
+
             var writeModel = new VendorCompanyRosterWriteModel
             {
                 Name = dto.Name,
@@ -71,6 +82,8 @@ namespace SeaHaven.Services.Implementation
                 Zip = dto.Zip,
                 GoogleMapsUrl = dto.GoogleMapsUrl,
                 Notes = dto.Notes,
+                AreaIdProvided = true,
+                AreaId = dto.AreaId,
                 ActorUserId = userId,
                 Technicians = MapTechnicians(dto.Technicians)
             };
@@ -83,6 +96,7 @@ namespace SeaHaven.Services.Implementation
             int companyId,
             ReconcileVendorRosterDTO dto,
             string userId,
+            ClaimsPrincipal caller,
             CancellationToken cancellationToken)
         {
             EnsureAuthenticated(userId);
@@ -101,6 +115,14 @@ namespace SeaHaven.Services.Implementation
             // Mismatched ids: every non-null technician id must belong to this company.
             await EnsureTechnicianIdsBelongToCompanyAsync(companyId, dto.Technicians, cancellationToken);
 
+            if (dto.AreaIdProvided)
+                await EnsureAreaChangeAllowedAsync(
+                    companyId,
+                    caller,
+                    dto.AreaId,
+                    nameof(ReconcileVendorRosterDTO.AreaId),
+                    cancellationToken);
+
             var writeModel = new VendorCompanyRosterWriteModel
             {
                 CompanyId = companyId,
@@ -114,6 +136,8 @@ namespace SeaHaven.Services.Implementation
                 Zip = dto.Zip,
                 GoogleMapsUrl = dto.GoogleMapsUrl,
                 Notes = dto.Notes,
+                AreaIdProvided = dto.AreaIdProvided,
+                AreaId = dto.AreaId,
                 ActorUserId = userId,
                 Technicians = MapTechnicians(dto.Technicians)
             };
@@ -126,6 +150,7 @@ namespace SeaHaven.Services.Implementation
             int companyId,
             AddTechniciansVendorRosterDTO dto,
             string userId,
+            ClaimsPrincipal caller,
             CancellationToken cancellationToken)
         {
             EnsureAuthenticated(userId);
@@ -167,6 +192,14 @@ namespace SeaHaven.Services.Implementation
             if (failures.Count > 0)
                 throw new ValidationException(failures);
 
+            if (companyFields is { AreaIdProvided: true })
+                await EnsureAreaChangeAllowedAsync(
+                    companyId,
+                    caller,
+                    companyFields.AreaId,
+                    $"{nameof(AddTechniciansVendorRosterDTO.CompanyFields)}.{nameof(VendorRosterCompanyFieldsDTO.AreaId)}",
+                    cancellationToken);
+
             // The contact-group invariant ("at least one company phone or email") is
             // preserved by construction: blank company fields map to null ("unchanged"),
             // so this endpoint can only set valid phone/email values, never clear them.
@@ -184,6 +217,50 @@ namespace SeaHaven.Services.Implementation
             return MapToDTO(saved);
         }
 
+        // SH-278: Area assignment is Admin-only. A payload that leaves the stored Area
+        // unchanged is allowed for any authenticated caller, so non-admin users can
+        // still save other company fields while round-tripping the current Area.
+        private async Task EnsureAreaChangeAllowedAsync(
+            int companyId,
+            ClaimsPrincipal caller,
+            int? requestedAreaId,
+            string propertyName,
+            CancellationToken cancellationToken)
+        {
+            var roster = await _rosterDataService.GetRosterAsync(null, companyId, cancellationToken)
+                ?? throw new KeyNotFoundException($"Vendor company with ID {companyId} not found.");
+
+            await EnsureAreaAssignmentAllowedAsync(
+                caller,
+                requestedAreaId,
+                roster.AreaId,
+                propertyName,
+                cancellationToken);
+        }
+
+        private async Task EnsureAreaAssignmentAllowedAsync(
+            ClaimsPrincipal caller,
+            int? requestedAreaId,
+            int? currentAreaId,
+            string propertyName,
+            CancellationToken cancellationToken)
+        {
+            if (requestedAreaId == currentAreaId)
+                return;
+
+            if (caller?.IsInRole(AdminRole) != true)
+                throw new VendorAreaAssignmentForbiddenException();
+
+            if (requestedAreaId is int areaId
+                && (areaId <= 0 || !await _rosterDataService.IsActiveAreaAsync(areaId, cancellationToken)))
+            {
+                throw new ValidationException(new[]
+                {
+                    new ValidationFailure(propertyName, AreaNotFoundMessage)
+                });
+            }
+        }
+
         private static void EnsureAuthenticated(string userId)
         {
             if (string.IsNullOrWhiteSpace(userId))
@@ -290,7 +367,8 @@ namespace SeaHaven.Services.Implementation
             || !string.IsNullOrWhiteSpace(fields.State)
             || !string.IsNullOrWhiteSpace(fields.Zip)
             || !string.IsNullOrWhiteSpace(fields.GoogleMapsUrl)
-            || !string.IsNullOrWhiteSpace(fields.Notes);
+            || !string.IsNullOrWhiteSpace(fields.Notes)
+            || fields.AreaIdProvided;
 
         private static bool HasNoCompanyChange(VendorRosterCompanyFieldsWriteModel model) =>
             model.Name == null
@@ -301,7 +379,8 @@ namespace SeaHaven.Services.Implementation
             && model.State == null
             && model.Zip == null
             && model.GoogleMapsUrl == null
-            && model.Notes == null;
+            && model.Notes == null
+            && !model.AreaIdProvided;
 
         private static VendorRosterCompanyFieldsWriteModel ValidateAndMapCompanyFields(
             VendorRosterCompanyFieldsDTO fields,
@@ -344,7 +423,9 @@ namespace SeaHaven.Services.Implementation
                 State = string.IsNullOrWhiteSpace(fields.State) ? null : fields.State,
                 Zip = string.IsNullOrWhiteSpace(fields.Zip) ? null : fields.Zip,
                 GoogleMapsUrl = string.IsNullOrWhiteSpace(fields.GoogleMapsUrl) ? null : fields.GoogleMapsUrl,
-                Notes = string.IsNullOrWhiteSpace(fields.Notes) ? null : fields.Notes
+                Notes = string.IsNullOrWhiteSpace(fields.Notes) ? null : fields.Notes,
+                AreaIdProvided = fields.AreaIdProvided,
+                AreaId = fields.AreaId
             };
         }
 
@@ -443,6 +524,8 @@ namespace SeaHaven.Services.Implementation
             Zip = roster.Zip,
             GoogleMapsUrl = roster.GoogleMapsUrl,
             Notes = roster.Notes,
+            AreaId = roster.AreaId,
+            AreaName = roster.AreaName,
             RowVersion = roster.RowVersion == null ? null : Convert.ToBase64String(roster.RowVersion),
             Technicians = roster.Technicians.Select(t => new VendorRosterTechnicianDTO
             {

SeaHaven.Services/Implementation/VendorService.cs

@@ -4,6 +4,7 @@ using FluentValidation;
 using FluentValidation.Results;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using System.Globalization;
 using SeaHaven.DataServices.Interfaces;
 using SeaHaven.DataServices.Models;
 using SeaHaven.Services.Configuration;
@@ -160,10 +161,12 @@ namespace SeaHaven.Services.Implementation
             IReadOnlyCollection<string>? trades = null,
             IReadOnlyCollection<string>? locations = null,
             IReadOnlyCollection<string>? jobBuckets = null,
+            IReadOnlyCollection<string>? areas = null,
             CancellationToken cancellationToken = default)
         {
             var normalizedPage = Math.Max(1, page);
             var normalizedPageSize = Math.Clamp(pageSize, 1, MaxDirectoryPageSize);
+            var areaFilter = await ResolveAreaFilterAsync(areas, cancellationToken);
             var (items, totalCount) = await _vendorDataService.GetCompanyDirectoryPagedAsync(
                 normalizedPage,
                 normalizedPageSize,
@@ -173,6 +176,7 @@ namespace SeaHaven.Services.Implementation
                 trades,
                 locations,
                 jobBuckets,
+                areaFilter,
                 cancellationToken);
 
             return new PagedResult<VendorDirectoryItemDTO>
@@ -184,6 +188,47 @@ namespace SeaHaven.Services.Implementation
             };
         }
 
+        // SH-278 areas[n] contract: blank entries are ignored; "__unassigned__" selects
+        // companies without an Area; other values must be stable positive integer ids
+        // of active catalogue rows. Display names, unknown ids and archived ids never
+        // error — they simply match nobody. Null means no Area filter was requested.
+        private async Task<VendorAreaFilter?> ResolveAreaFilterAsync(
+            IReadOnlyCollection<string>? areas,
+            CancellationToken cancellationToken)
+        {
+            var values = areas?
+                .Where(value => !string.IsNullOrWhiteSpace(value))
+                .Select(value => value.Trim())
+                .ToList();
+
+            if (values is not { Count: > 0 })
+                return null;
+
+            var includeUnassigned = values.Contains(VendorAreaFilterValues.Unassigned, StringComparer.Ordinal);
+            var requestedIds = new HashSet<int>();
+            foreach (var value in values)
+            {
+                if (int.TryParse(value, NumberStyles.None, CultureInfo.InvariantCulture, out var id) && id > 0)
+                    requestedIds.Add(id);
+            }
+
+            IReadOnlyCollection<int> activeIds = Array.Empty<int>();
+            if (requestedIds.Count > 0)
+            {
+                var activeAreas = await _vendorDataService.GetActiveAreasAsync(cancellationToken);
+                activeIds = activeAreas
+                    .Select(area => area.Id)
+                    .Where(requestedIds.Contains)
+                    .ToArray();
+            }
+
+            return new VendorAreaFilter
+            {
+                AreaIds = activeIds,
+                IncludeUnassigned = includeUnassigned
+            };
+        }
+
         private static VendorDirectoryItemDTO MapToCompanyGroup(VendorCompanyGroup group) => new()
         {
             Id = group.Id,
@@ -201,6 +246,8 @@ namespace SeaHaven.Services.Implementation
             TradeSpecialties = group.TradeSpecialties,
             GoogleMapsUrl = group.GoogleMapsUrl,
             Notes = group.Notes,
+            AreaId = group.AreaId,
+            AreaName = group.AreaName,
             IsActive = group.IsActive,
             TotalJobs = group.TotalJobs,
             Technicians = group.Technicians.Select(MapToTechnician).ToList()
@@ -731,6 +778,7 @@ namespace SeaHaven.Services.Implementation
             // populated even on an empty database and independent of the status filter.
             var companies = await _vendorDataService.GetCompaniesForFacetsAsync(isActive, cancellationToken);
             var canonicalTrades = await _vendorDataService.GetActiveTradesAsync(cancellationToken);
+            var activeAreas = await _vendorDataService.GetActiveAreasAsync(cancellationToken);
 
             var companyFacets = companies
                 .Where(c => !string.IsNullOrWhiteSpace(c.Name))
@@ -772,10 +820,19 @@ namespace SeaHaven.Services.Implementation
                 .DistinctBy(location => location.Label, StringComparer.OrdinalIgnoreCase)
                 .OrderBy(location => location.Label);
 
+            // SH-278: the active Area catalogue, A–Z case-insensitive, independent of the
+            // status filter and of whether any company currently uses an Area. Clients
+            // prepend the "__unassigned__" option themselves.
+            var areas = activeAreas
+                .OrderBy(area => area.Name, StringComparer.OrdinalIgnoreCase)
+                .Select(area => new VendorFacetAreaDTO { Id = area.Id, Name = area.Name })
+                .ToList();
+
             return new VendorFacetsDTO
             {
                 Companies = companyFacets,
                 Trades = trades,
+                Areas = areas,
                 Locations = locations,
                 JobBuckets = new[]
                 {

SeaHaven.Services/Interfaces/IVendorCompanyRosterService.cs

@@ -1,3 +1,4 @@
+using System.Security.Claims;
 using SeaHaven.Services.DTOs;
 
 namespace SeaHaven.Services.Interfaces
@@ -13,18 +14,21 @@ namespace SeaHaven.Services.Interfaces
         Task<VendorRosterDTO> CreateRosterAsync(
             CreateVendorRosterDTO dto,
             string userId,
+            ClaimsPrincipal caller,
             CancellationToken cancellationToken);
 
         Task<VendorRosterDTO> ReconcileRosterAsync(
             int companyId,
             ReconcileVendorRosterDTO dto,
             string userId,
+            ClaimsPrincipal caller,
             CancellationToken cancellationToken);
 
         Task<VendorRosterDTO> AddTechniciansAsync(
             int companyId,
             AddTechniciansVendorRosterDTO dto,
             string userId,
+            ClaimsPrincipal caller,
             CancellationToken cancellationToken);
     }
 }

SeaHaven.Services/Interfaces/IVendorService.cs

@@ -41,6 +41,7 @@ namespace SeaHaven.Services.Interfaces
             IReadOnlyCollection<string>? trades = null,
             IReadOnlyCollection<string>? locations = null,
             IReadOnlyCollection<string>? jobBuckets = null,
+            IReadOnlyCollection<string>? areas = null,
             CancellationToken cancellationToken = default);
         Task<VendorDTO> CreateVendorAsync(CreateVendorDTO dto, string userId);
         Task<VendorDTO> UpdateVendorAsync(int id, UpdateVendorDTO dto, string userId);