fix(team-members): keep full-name round-trip stable on update

Storing the submitted full name in FirstName while leaving a seeded
LastName intact made an unchanged save project a duplicated name
(e.g. "Legacy Manager Manager"). Leave FirstName/LastName untouched when
the submitted name already matches the stored first+last projection, and
otherwise split the submitted name across FirstName/LastName so renames
round-trip cleanly.

Api.SeaHavenIndustries.Tests/TeamMemberServiceTests.cs

@@ -216,6 +216,57 @@ public sealed class TeamMemberServiceTests
         overrides.Verify(data => data.SetOverridesAsync(user.Id, It.Is<IReadOnlyDictionary<string, UserPermissionState>>(value => value["createSites"] == UserPermissionState.Deny), It.IsAny<CancellationToken>()), Times.Once);
     }
 
+    [Fact]
+    public async Task Update_SavesUnchangedNameWithoutDuplicatingRoleLikeLastName()
+    {
+        var service = NewService(
+            out var userManager,
+            out var roleManager,
+            out var areas,
+            out _,
+            out var userData,
+            out var permissions);
+        var user = new ApplicationUser
+        {
+            Id = "admin",
+            FirstName = "Legacy",
+            LastName = "Manager",
+            Email = "legacy@example.com",
+            Color = "#F59E0B",
+            UniqueName = "Active"
+        };
+        userManager.Setup(manager => manager.FindByIdAsync(user.Id)).ReturnsAsync(user);
+        userManager.Setup(manager => manager.GetRolesAsync(user)).ReturnsAsync(new List<string> { "Admin" });
+        userManager.Setup(manager => manager.FindByEmailAsync(user.Email!)).ReturnsAsync(user);
+        roleManager.Setup(manager => manager.RoleExistsAsync("Admin")).ReturnsAsync(true);
+        areas.Setup(data => data.GetForUserAsync(user.Id, It.IsAny<CancellationToken>()))
+            .ReturnsAsync(Array.Empty<string>());
+        permissions.Setup(data => data.GetProfileAsync(user.Id, It.IsAny<ClaimsPrincipal>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync(TeamPermissionResult<TeamPermissionProfileDTO>.Success(new TeamPermissionProfileDTO
+            {
+                UserId = user.Id,
+                Permissions = Array.Empty<TeamPermissionValueDTO>()
+            }));
+
+        var result = await service.UpdateAsync(
+            user.Id,
+            new UpdateTeamMemberRequestDTO
+            {
+                Name = "Legacy Manager",
+                Role = "Admin",
+                Color = "#F59E0B",
+                Email = user.Email
+            },
+            Admin(),
+            CancellationToken.None);
+
+        result.Success.Should().BeTrue();
+        user.FirstName.Should().Be("Legacy");
+        user.LastName.Should().Be("Manager");
+        result.Member!.Name.Should().Be("Legacy Manager");
+        userData.Verify(data => data.UpdateUserAsync(user, It.IsAny<CancellationToken>()), Times.Once);
+    }
+
     [Fact]
     public async Task Update_LeavesOmittedOverridesUnchanged()
     {

SeaHaven.Services/Implementation/TeamMemberService.cs

@@ -167,7 +167,7 @@ public sealed class TeamMemberService : ITeamMemberService
         if (roleError is not null)
             return OperationFailure(roleError);
 
-        user.FirstName = candidate.Name!.Trim();
+        ApplyName(user, candidate.Name!.Trim());
         user.Contact = candidate.Phone?.Trim();
         user.PhoneNumber = candidate.Phone?.Trim();
         user.Color = color;
@@ -215,6 +215,24 @@ public sealed class TeamMemberService : ITeamMemberService
         return await OperationSuccessAsync(user, caller, cancellationToken);
     }
 
+    private static void ApplyName(ApplicationUser user, string fullName)
+    {
+        var current = $"{user.FirstName ?? ""} {user.LastName ?? ""}".Trim();
+        if (string.Equals(fullName, current, StringComparison.Ordinal))
+            return;
+
+        var separator = fullName.IndexOf(' ');
+        if (separator < 0)
+        {
+            user.FirstName = fullName;
+            user.LastName = null;
+            return;
+        }
+
+        user.FirstName = fullName[..separator].Trim();
+        user.LastName = fullName[(separator + 1)..].Trim();
+    }
+
     private async Task<string?> EnsureRoleAsync(string role)
     {
         if (await _roleManager.RoleExistsAsync(role))