Add FlatPaymentController with RESTful payment endpoints

Introduced FlatPaymentController under Distribution.Features.Payment, providing GET and POST endpoints at /api/payments. Supports listing, retrieving, and creating payments with filtering and error handling. Business logic is delegated to PaymentService.

Distribution/Features/LoadingEvent/LoadingSheetController.cs

@@ -100,4 +100,43 @@ public class LoadingSheetController(LoadingSheetService service, ICurrentUserSer
         catch (KeyNotFoundException) { return NotFound(); }
         catch (InvalidOperationException ex) { return BadRequest(new { error = ex.Message }); }
     }
+
+    [HttpPatch("{id:guid}/dispatch")]
+    public async Task<IActionResult> PatchDispatch(Guid id, CancellationToken ct)
+    {
+        var userId = currentUser.UserId ?? throw new UnauthorizedAccessException();
+        try
+        {
+            var result = await service.ConfirmDispatchAsync(id, userId, ct);
+            return Ok(result);
+        }
+        catch (KeyNotFoundException) { return NotFound(); }
+        catch (InvalidOperationException ex) { return BadRequest(new { error = ex.Message }); }
+    }
+
+    [HttpPatch("{id:guid}/receipt")]
+    public async Task<IActionResult> PatchReceipt(Guid id, PatchReceiptRequest request, CancellationToken ct)
+    {
+        var userId = currentUser.UserId ?? throw new UnauthorizedAccessException();
+        try
+        {
+            var result = await service.PatchReceiptAsync(id, request.Items, userId, ct);
+            return Ok(result);
+        }
+        catch (KeyNotFoundException) { return NotFound(); }
+        catch (InvalidOperationException ex) { return BadRequest(new { error = ex.Message }); }
+    }
+
+    [HttpPatch("{id:guid}/resolve")]
+    public async Task<IActionResult> PatchResolve(Guid id, CancellationToken ct)
+    {
+        var userId = currentUser.UserId ?? throw new UnauthorizedAccessException();
+        try
+        {
+            var result = await service.PatchResolveAsync(id, userId, ct);
+            return Ok(result);
+        }
+        catch (KeyNotFoundException) { return NotFound(); }
+        catch (InvalidOperationException ex) { return BadRequest(new { error = ex.Message }); }
+    }
 }