Add ChangeAssignment endpoint with audit logging

- POST /api/WorkOrder/ChangeAssignment?id=&assignTo=
- Logs old and new user names in audit trail
- Returns updated assignment name

Api.SeaHavenIndustries/Controllers/WorkOrderController.cs

@@ -785,6 +785,43 @@ namespace Api.SeaHavenIndustries.Controllers
             }
         }
 
+        [HttpPost]
+        [Route("ChangeAssignment")]
+        public async Task<IActionResult> ChangeAssignment(int id, string? assignTo)
+        {
+            try
+            {
+                var data = await _db.workOrders.Where(w => w.Id == id).FirstOrDefaultAsync();
+                if (data == null)
+                    return BadRequest(new Response { Status = "Error", Message = "Work order not found" });
+                if (data.AssignTo != assignTo)
+                {
+                    var oldUser = data.AssignTo != null ? await _db.Users.FindAsync(data.AssignTo) : null;
+                    var newUser = assignTo != null ? await _db.Users.FindAsync(assignTo) : null;
+                    _db.WorkOrderAuditLogs.Add(new WorkOrderAuditLog
+                    {
+                        WorkOrderId = id,
+                        UserId = User.FindFirstValue(ClaimTypes.NameIdentifier),
+                        FieldName = "AssignedTo",
+                        OldValue = oldUser != null ? (oldUser.FirstName + " " + oldUser.LastName).Trim() : "",
+                        NewValue = newUser != null ? (newUser.FirstName + " " + newUser.LastName).Trim() : "Unassigned",
+                        Action = "assignment_change",
+                        CreatedAt = DateTime.UtcNow
+                    });
+                }
+                data.AssignTo = assignTo;
+                await _db.SaveChangesAsync();
+
+                var assignedUser = assignTo != null ? await _db.Users.FindAsync(assignTo) : null;
+                var assignedName = assignedUser != null ? (assignedUser.FirstName + " " + assignedUser.LastName).Trim() : "";
+                return Ok(new { message = "Updated Successfully", assignedTo = assignedName });
+            }
+            catch (Exception ex)
+            {
+                return BadRequest(new Response { Status = "Error", Message = ex.Message });
+            }
+        }
+
         [HttpPost]
         [Route("AddComment")]
         public async Task<IActionResult> AddComment([FromForm] Comments_DTO model)