Fix user ID handling in purchase return creation when auth is unavailable

Distribution/Features/PurchaseReturn/PurchaseReturnController.cs

@@ -20,10 +20,13 @@ public class PurchaseReturnController(PurchaseReturnService service, ICurrentUse
     [HttpPost("api/purchase-orders/{id:guid}/returns")]
     public async Task<IActionResult> Create(Guid id, CreatePurchaseReturnRequest request, CancellationToken ct)
     {
-        var userId = currentUser.UserId ?? throw new UnauthorizedAccessException();
+        // TEMPORARY: currentUser.UserId is always unset due to the broken auth middleware
+        // (testbug.md #28) — fall back to the explicitly supplied user until that's fixed.
+        var userId = currentUser.UserId ?? request.CreatedByUserId;
+        if (userId is null) return BadRequest(new { error = "CreatedByUserId is required while auth is unavailable" });
         try
         {
-            var result = await service.CreateAsync(id, request, userId, ct);
+            var result = await service.CreateAsync(id, request, userId.Value, ct);
             return CreatedAtAction(nameof(GetById), new { id = result.Id }, result);
         }
         catch (InvalidOperationException ex) { return Conflict(new { error = ex.Message }); }

Distribution/Features/PurchaseReturn/PurchaseReturnDTOs.cs

@@ -2,7 +2,11 @@ namespace Distribution.Features.PurchaseReturn;
 
 public record PurchaseReturnItemRequest(Guid ItemId, int Quantity);
 
-public record CreatePurchaseReturnRequest(string Reason, List<PurchaseReturnItemRequest> Items);
+public record CreatePurchaseReturnRequest(
+    string Reason,
+    List<PurchaseReturnItemRequest> Items,
+    // TEMPORARY: required while auth doesn't resolve a logged-in user server-side — see testbug.md #28.
+    Guid? CreatedByUserId = null);
 
 public record PurchaseReturnItemResponse(Guid Id, Guid ItemId, string Sku, string ItemName, int Quantity);