Merge upstream/main: v0.1.61 updates with TOTP & password reset

Major features:
- feat(auth): add TOTP (2FA) support for enhanced security
- feat(auth): add password reset functionality
- feat(openai): improve rate limit handling with reset time tracking
- feat(subscription): add expiry notification service
- fix(urlvalidator): remove trailing slash from validated URLs
- docs: update demo site domain

Resolved conflicts:
- deploy/docker-compose.yml: added TOTP_ENCRYPTION_KEY config
- setting_service.go: keep TianShuAPI site name while adding new features

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/internal/server/api_contract_test.go

@@ -197,7 +197,7 @@ func TestAPIContracts(t *testing.T) {
 						UserID:          1,
 						GroupID:         10,
 						StartsAt:        deps.now,
-						ExpiresAt:       deps.now.Add(24 * time.Hour),
+						ExpiresAt:       time.Date(2099, 1, 2, 3, 4, 5, 0, time.UTC), // 使用未来日期避免 normalizeSubscriptionStatus 标记为过期
 						Status:          service.SubscriptionStatusActive,
 						DailyUsageUSD:   1.23,
 						WeeklyUsageUSD:  2.34,
@@ -222,7 +222,7 @@ func TestAPIContracts(t *testing.T) {
 						"user_id": 1,
 						"group_id": 10,
 						"starts_at": "2025-01-02T03:04:05Z",
-						"expires_at": "2025-01-03T03:04:05Z",
+						"expires_at": "2099-01-02T03:04:05Z",
 						"status": "active",
 						"daily_window_start": null,
 						"weekly_window_start": null,
@@ -452,6 +452,9 @@ func TestAPIContracts(t *testing.T) {
 					"registration_enabled": true,
 					"email_verify_enabled": false,
 					"promo_code_enabled": true,
+					"password_reset_enabled": false,
+					"totp_enabled": false,
+					"totp_encryption_key_configured": false,
 					"smtp_host": "smtp.example.com",
 					"smtp_port": 587,
 					"smtp_username": "user",
@@ -595,7 +598,7 @@ func newContractDeps(t *testing.T) *contractDeps {
 	settingService := service.NewSettingService(settingRepo, cfg)
 
 	adminService := service.NewAdminService(userRepo, groupRepo, &accountRepo, proxyRepo, apiKeyRepo, redeemRepo, nil, nil, nil, nil)
-	authHandler := handler.NewAuthHandler(cfg, nil, userService, settingService, nil)
+	authHandler := handler.NewAuthHandler(cfg, nil, userService, settingService, nil, nil)
 	apiKeyHandler := handler.NewAPIKeyHandler(apiKeyService)
 	usageHandler := handler.NewUsageHandler(usageService, apiKeyService)
 	adminSettingHandler := adminhandler.NewSettingHandler(settingService, nil, nil, nil)
@@ -754,6 +757,18 @@ func (r *stubUserRepo) RemoveGroupFromAllowedGroups(ctx context.Context, groupID
 	return 0, errors.New("not implemented")
 }
 
+func (r *stubUserRepo) UpdateTotpSecret(ctx context.Context, userID int64, encryptedSecret *string) error {
+	return errors.New("not implemented")
+}
+
+func (r *stubUserRepo) EnableTotp(ctx context.Context, userID int64) error {
+	return errors.New("not implemented")
+}
+
+func (r *stubUserRepo) DisableTotp(ctx context.Context, userID int64) error {
+	return errors.New("not implemented")
+}
+
 type stubApiKeyCache struct{}
 
 func (stubApiKeyCache) GetCreateAttemptCount(ctx context.Context, userID int64) (int, error) {
@@ -1176,7 +1191,7 @@ func (r *stubUserSubscriptionRepo) ListActiveByUserID(ctx context.Context, userI
 func (stubUserSubscriptionRepo) ListByGroupID(ctx context.Context, groupID int64, params pagination.PaginationParams) ([]service.UserSubscription, *pagination.PaginationResult, error) {
 	return nil, nil, errors.New("not implemented")
 }
-func (stubUserSubscriptionRepo) List(ctx context.Context, params pagination.PaginationParams, userID, groupID *int64, status string) ([]service.UserSubscription, *pagination.PaginationResult, error) {
+func (stubUserSubscriptionRepo) List(ctx context.Context, params pagination.PaginationParams, userID, groupID *int64, status, sortBy, sortOrder string) ([]service.UserSubscription, *pagination.PaginationResult, error) {
 	return nil, nil, errors.New("not implemented")
 }
 func (stubUserSubscriptionRepo) ExistsByUserIDAndGroupID(ctx context.Context, userID, groupID int64) (bool, error) {