feat: Refactor user context handling and service methods

- Updated middleware to fetch user and tenant models by ID and set them in context.
- Refactored common service methods to accept userID as a parameter instead of extracting from context.
- Modified content service methods to include userID as a parameter for better clarity and performance.
- Adjusted coupon, creator, notification, order, tenant, user, and wallet services to utilize userID directly.
- Enhanced context key constants for improved readability and maintainability.

backend/app/commands/seed/seed.go

@@ -120,13 +120,13 @@ func Serve(cmd *cobra.Command, args []string) error {
 				UserID:      creator.ID,
 				Title:       title,
 				Description: fmt.Sprintf("这是关于 %s 的详细介绍...", title),
-							Genre:       "京剧",
-							Status:      consts.ContentStatusPublished,
-							Visibility:  consts.ContentVisibilityPublic,
-							Views:       int32(rand.Intn(10000)),
-							Likes:       int32(rand.Intn(1000)),
-						}
-						models.ContentQuery.WithContext(ctx).Create(c)
+				Genre:       "京剧",
+				Status:      consts.ContentStatusPublished,
+				Visibility:  consts.ContentVisibilityPublic,
+				Views:       int32(rand.Intn(10000)),
+				Likes:       int32(rand.Intn(1000)),
+			}
+			models.ContentQuery.WithContext(ctx).Create(c)
 			// Price
 			models.ContentPriceQuery.WithContext(ctx).Create(&models.ContentPrice{
 				TenantID:    tenant.ID,