Drop qt_users dependency for configs and track app version

internal/services/sync/service.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"time"
 
+	"git.mchus.pro/mchus/quoteforge/internal/appmeta"
 	"git.mchus.pro/mchus/quoteforge/internal/db"
 	"git.mchus.pro/mchus/quoteforge/internal/localdb"
 	"git.mchus.pro/mchus/quoteforge/internal/models"
@@ -605,15 +606,10 @@ func (s *Service) ensureConfigurationOwner(mariaDB *gorm.DB, cfg *models.Configu
 		return fmt.Errorf("owner username is empty")
 	}
 
-	userID, err := models.EnsureDBUser(mariaDB, ownerUsername)
-	if err != nil {
-		return err
-	}
-	if userID == 0 {
-		return fmt.Errorf("resolved user ID is 0 for owner %q", ownerUsername)
-	}
-
-	cfg.UserID = userID
+	// user_id is legacy and no longer used for ownership in local-first mode.
+	// Keep it NULL on writes; ownership is represented by owner_username.
+	cfg.UserID = nil
+	cfg.AppVersion = appmeta.Version()
 	return nil
 }