fix(work-orders): persist empty apptTime as null scheduled instants

EOF

SeaHaven.Services/Helpers/WorkOrderBoardApptTimeParser.cs

@@ -53,5 +53,8 @@ namespace SeaHaven.Services.Helpers
 
             return date.Value.Date.Add(time.Value);
         }
+
+        public static DateTime? ToScheduledInstant(DateTime? date, TimeSpan? time)
+            => time.HasValue ? CombineDateAndTime(date, time) : null;
     }
 }

SeaHaven.Services/Helpers/WorkOrderBoardFieldMutations.cs

@@ -87,8 +87,8 @@ namespace SeaHaven.Services.Helpers
             var oldStart = FormatDateTime(workOrder.ScheduledStart);
             var oldEnd = FormatDateTime(workOrder.ScheduledEnd);
 
-            workOrder.ScheduledStart = WorkOrderBoardApptTimeParser.CombineDateAndTime(apptDate, start);
+            workOrder.ScheduledStart = WorkOrderBoardApptTimeParser.ToScheduledInstant(apptDate, start);
-            workOrder.ScheduledEnd = WorkOrderBoardApptTimeParser.CombineDateAndTime(apptDate, end);
+            workOrder.ScheduledEnd = WorkOrderBoardApptTimeParser.ToScheduledInstant(apptDate, end);
 
             var newStart = FormatDateTime(workOrder.ScheduledStart);
             var newEnd = FormatDateTime(workOrder.ScheduledEnd);

SeaHaven.Services/Implementation/WorkOrderBoardService.cs

@@ -85,8 +85,10 @@ namespace SeaHaven.Services.Implementation
         public static WorkOrderBoardRowDto MapRawRow(WorkOrderBoardRawRow row, DateTime utcNow)
         {
             // Appt column: date prefers dispatch appointment (vendor slot), then WO ScheduledDate.
-            // Time prefers WO ScheduledStart/End (dispatcher window), then dispatch datetime.
+            // Time uses WO ScheduledStart/End only. Do not fall back to a date-only dispatch
-            var apptStart = row.ScheduledStart ?? row.DispatchApptDate;
+            // instant (midnight), or clearing apptTime still renders 00:00.
+            var apptStart = row.ScheduledStart
+                ?? (HasClockTime(row.DispatchApptDate) ? row.DispatchApptDate : null);
             var apptEnd = row.ScheduledEnd;
             var (vendorId, vendorName) = WorkOrderBoardDispatchAssignment.LiveVendor(
                 row.VendorId,
@@ -145,6 +147,9 @@ namespace SeaHaven.Services.Implementation
             };
         }
 
+        private static bool HasClockTime(DateTime? value)
+            => value.HasValue && value.Value.TimeOfDay != TimeSpan.Zero;
+
         private static string FormatName(string? firstName, string? lastName)
             => $"{firstName ?? ""} {lastName ?? ""}".Trim();
 

SeaHaven.Services/Implementation/WorkOrderBoardUpdateService.cs

@@ -651,8 +651,8 @@ namespace SeaHaven.Services.Implementation
             var oldEnd = FormatDateTime(workOrder.ScheduledEnd);
             var dispatchId = ResolveDispatchIdForAudit(dispatch);
 
-            workOrder.ScheduledStart = WorkOrderBoardApptTimeParser.CombineDateAndTime(apptDate, start);
+            workOrder.ScheduledStart = WorkOrderBoardApptTimeParser.ToScheduledInstant(apptDate, start);
-            workOrder.ScheduledEnd = WorkOrderBoardApptTimeParser.CombineDateAndTime(apptDate, end);
+            workOrder.ScheduledEnd = WorkOrderBoardApptTimeParser.ToScheduledInstant(apptDate, end);
 
             var newStart = FormatDateTime(workOrder.ScheduledStart);
             var newEnd = FormatDateTime(workOrder.ScheduledEnd);

SeaHavenIndustries.Tests/WorkOrderBoardFieldMutationsTests.cs

@@ -0,0 +1,53 @@
+using Data.SeaHavenIndustries;
+using SeaHaven.Services.Helpers;
+
+namespace SeaHavenIndustries.Tests;
+
+public class WorkOrderBoardFieldMutationsTests
+{
+    [Fact]
+    public void ApplyApptTime_EmptyValue_ClearsStartAndEnd_KeepsDates()
+    {
+        var appointmentDate = new DateTime(2026, 6, 25);
+        var workOrder = new WorkOrder
+        {
+            ScheduledDate = appointmentDate,
+            ScheduledStart = new DateTime(2026, 6, 25, 9, 0, 0),
+            ScheduledEnd = new DateTime(2026, 6, 25, 11, 0, 0)
+        };
+        var dispatch = new Dispatch { Id = 10, ScheduledDate = appointmentDate };
+
+        WorkOrderBoardFieldMutations.ApplyApptTime(workOrder, dispatch, "");
+
+        Assert.Null(workOrder.ScheduledStart);
+        Assert.Null(workOrder.ScheduledEnd);
+        Assert.Equal(appointmentDate, workOrder.ScheduledDate);
+        Assert.Equal(appointmentDate, dispatch.ScheduledDate);
+    }
+
+    [Fact]
+    public void ApplyApptTime_StartOnly_LeavesEndNull()
+    {
+        var appointmentDate = new DateTime(2026, 6, 25);
+        var workOrder = new WorkOrder { ScheduledDate = appointmentDate };
+        var dispatch = new Dispatch { Id = 10, ScheduledDate = appointmentDate };
+
+        WorkOrderBoardFieldMutations.ApplyApptTime(workOrder, dispatch, "09:00");
+
+        Assert.Equal(new DateTime(2026, 6, 25, 9, 0, 0), workOrder.ScheduledStart);
+        Assert.Null(workOrder.ScheduledEnd);
+    }
+
+    [Fact]
+    public void ApplyApptTime_Range_SetsStartAndEnd()
+    {
+        var appointmentDate = new DateTime(2026, 6, 25);
+        var workOrder = new WorkOrder { ScheduledDate = appointmentDate };
+        var dispatch = new Dispatch { Id = 10, ScheduledDate = appointmentDate };
+
+        WorkOrderBoardFieldMutations.ApplyApptTime(workOrder, dispatch, "09:00 – 11:00");
+
+        Assert.Equal(new DateTime(2026, 6, 25, 9, 0, 0), workOrder.ScheduledStart);
+        Assert.Equal(new DateTime(2026, 6, 25, 11, 0, 0), workOrder.ScheduledEnd);
+    }
+}

SeaHavenIndustries.Tests/WorkOrderBoardUpdateServiceTests.cs

@@ -1070,6 +1070,53 @@ public class WorkOrderBoardUpdateServiceTests
         Assert.Equal(new DateTime(2026, 6, 25, 10, 0, 0), reloaded.ScheduledEnd);
     }
 
+    [Fact]
+    public async Task PatchField_ApptTime_EmptyClearsStartAndEnd_KeepsAppointmentDate()
+    {
+        var (context, service) = CreateSut();
+        var appointmentDate = new DateTime(2026, 6, 25);
+        var dispatch = new Dispatch
+        {
+            Id = 10,
+            WorkOrderId = 1,
+            VendorId = 1,
+            ScheduledDate = appointmentDate,
+            RowVersion = new byte[] { 1, 0, 0, 0, 0, 0, 0, 2 }
+        };
+        var wo = new WorkOrder
+        {
+            Id = 1,
+            LifecycleStatus = LifecycleStatus.Scheduled,
+            PrimaryDispatchId = 10,
+            ScheduledDate = appointmentDate,
+            ScheduledStart = new DateTime(2026, 6, 25, 9, 0, 0),
+            ScheduledEnd = new DateTime(2026, 6, 25, 11, 0, 0),
+            RowVersion = new byte[] { 1, 0, 0, 0, 0, 0, 0, 1 }
+        };
+        context.Vendors.Add(new Vendor { Id = 1, CompanyName = "Vendor A" });
+        context.Dispatches.Add(dispatch);
+        context.workOrders.Add(wo);
+        await context.SaveChangesAsync();
+
+        var result = await service.PatchFieldAsync(1, new WorkOrderBoardPatchRequestDto
+        {
+            Field = WorkOrderBoardFieldNames.ApptTime,
+            Value = "",
+            WorkOrderVersion = ToVersion(wo),
+            DispatchVersion = ToVersion(dispatch),
+            PrimaryDispatchId = 10
+        }, "actor-1");
+
+        Assert.True(string.IsNullOrEmpty(result.ApptTime));
+        Assert.Equal(appointmentDate, result.ScheduledDate);
+        var reloaded = await context.workOrders.FindAsync(1);
+        Assert.Null(reloaded!.ScheduledStart);
+        Assert.Null(reloaded.ScheduledEnd);
+        Assert.Equal(appointmentDate, reloaded.ScheduledDate);
+        var reloadedDispatch = await context.Dispatches.FindAsync(10);
+        Assert.Equal(appointmentDate, reloadedDispatch!.ScheduledDate);
+    }
+
     [Fact]
     public async Task PatchField_ApptTime_DashPrefixedToken_TreatedAsSingleStart()
     {