fix: make inbox confirmation retry safe

backend/internal/logic/inbox/service.go

@@ -158,18 +158,20 @@ func (s *Service) Analyze(itemIdentity string, userID uint) ([]Suggestion, error
 
 // Confirm 只按服务端保存的建议 identity 创建对象；全部写入和 Inbox 状态变更位于同一事务中。
 func (s *Service) Confirm(itemIdentity string, userID uint, selectedSuggestionIdentities []string) (ConfirmResult, error) {
-	selected, err := normalizeSelectedIdentities(selectedSuggestionIdentities)
-	if err != nil {
-		return ConfirmResult{}, err
-	}
 	result := ConfirmResult{}
-	err = s.database().Transaction(func(tx *gorm.DB) error {
+	err := s.database().Transaction(func(tx *gorm.DB) error {
 		item, err := findOwnedInboxItem(tx, itemIdentity, userID, true)
 		if err != nil {
 			return err
 		}
 		if item.Status != "open" {
-			return ErrInboxAlreadyConfirmed
+			result.CreatedCount, err = countConfirmedObjects(tx, item.ID, userID)
+			return err
+		}
+
+		selected, err := normalizeSelectedIdentities(selectedSuggestionIdentities)
+		if err != nil {
+			return err
 		}
 
 		var saved []models.SenlinAgentInboxSuggestion
@@ -198,6 +200,18 @@ func (s *Service) Confirm(itemIdentity string, userID uint, selectedSuggestionId
 	return result, err
 }
 
+func countConfirmedObjects(tx *gorm.DB, inboxItemID, userID uint) (int, error) {
+	total := int64(0)
+	for _, model := range []any{&models.SenlinAgentTask{}, &models.SenlinAgentNote{}, &models.SenlinAgentSource{}} {
+		var count int64
+		if err := tx.Model(model).Where("source_inbox_item_id = ? AND created_by = ?", inboxItemID, userID).Count(&count).Error; err != nil {
+			return 0, err
+		}
+		total += count
+	}
+	return int(total), nil
+}
+
 func findOwnedInboxItem(tx *gorm.DB, identity string, userID uint, lock bool) (*models.SenlinAgentInboxItem, error) {
 	var item models.SenlinAgentInboxItem
 	query := tx.Model(&models.SenlinAgentInboxItem{}).