fix: 增强SKU异步任务失败错误明细

src/Api/TakeoutSaaS.TenantApi/Controllers/ProductController.cs

@@ -396,7 +396,7 @@ public sealed class ProductController(
         {
             entity.Status = ProductSkuSaveJobStatus.Failed;
             entity.FailedCount = entity.ProgressTotal;
-            entity.ErrorMessage = Truncate(ex.Message, 2000);
+            entity.ErrorMessage = Truncate(BuildDetailedErrorMessage(ex), 2000);
             entity.FinishedAt = DateTime.UtcNow;
             await dbContext.SaveChangesAsync(cancellationToken);
             return ApiResponse<ProductSkuSaveJobResponse>.Error(ErrorCodes.InternalServerError, "SKU 保存任务创建失败");
@@ -1370,6 +1370,32 @@ public sealed class ProductController(
         return value.Length <= maxLength ? value : value[..maxLength];
     }
 
+    private static string BuildDetailedErrorMessage(Exception ex)
+    {
+        var lines = new List<string>();
+        var current = ex;
+        var depth = 0;
+        const int maxDepth = 8;
+
+        while (current is not null && depth < maxDepth)
+        {
+            var prefix = depth == 0 ? "Exception" : $"Inner[{depth}]";
+            var message = string.IsNullOrWhiteSpace(current.Message)
+                ? "(no message)"
+                : current.Message.Trim();
+            lines.Add($"{prefix} {current.GetType().Name}: {message}");
+            current = current.InnerException;
+            depth++;
+        }
+
+        if (current is not null)
+        {
+            lines.Add($"Inner[{depth}] ...");
+        }
+
+        return string.Join(Environment.NewLine, lines);
+    }
+
     private async Task<ProductRelationState> LoadProductRelationStateAsync(
         long productId,
         long storeId,

src/Api/TakeoutSaaS.TenantApi/Services/ProductSkuSaveJobRunner.cs

@@ -44,7 +44,7 @@ public sealed class ProductSkuSaveJobRunner(
         catch (Exception ex)
         {
             logger.LogError(ex, "SKU 异步保存任务执行失败，JobId={JobId}", jobId);
-            await MarkFailedAsync(jobMeta.Id, ex.Message);
+            await MarkFailedAsync(jobMeta.Id, BuildDetailedErrorMessage(ex));
         }
     }
 
@@ -159,5 +159,31 @@ public sealed class ProductSkuSaveJobRunner(
         return value.Length <= maxLength ? value : value[..maxLength];
     }
 
+    private static string BuildDetailedErrorMessage(Exception ex)
+    {
+        var lines = new List<string>();
+        var current = ex;
+        var depth = 0;
+        const int maxDepth = 8;
+
+        while (current is not null && depth < maxDepth)
+        {
+            var prefix = depth == 0 ? "Exception" : $"Inner[{depth}]";
+            var message = string.IsNullOrWhiteSpace(current.Message)
+                ? "(no message)"
+                : current.Message.Trim();
+            lines.Add($"{prefix} {current.GetType().Name}: {message}");
+            current = current.InnerException;
+            depth++;
+        }
+
+        if (current is not null)
+        {
+            lines.Add($"Inner[{depth}] ...");
+        }
+
+        return string.Join(Environment.NewLine, lines);
+    }
+
     private sealed record JobMeta(long Id, long TenantId);
 }