Drop qt_users dependency for configs and track app version

internal/services/local_configuration.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"git.mchus.pro/mchus/quoteforge/internal/appmeta"
 	"git.mchus.pro/mchus/quoteforge/internal/localdb"
 	"git.mchus.pro/mchus/quoteforge/internal/models"
 	"git.mchus.pro/mchus/quoteforge/internal/services/sync"
@@ -820,6 +821,7 @@ func (s *LocalConfigurationService) appendVersionTx(
 			Data:              snapshot,
 			ChangeNote:        &changeNote,
 			CreatedBy:         createdByPtr,
+			AppVersion:        appmeta.Version(),
 		}
 
 		if err := tx.Create(version).Error; err != nil {
@@ -915,6 +917,7 @@ func (s *LocalConfigurationService) rollbackToVersion(configurationUUID string,
 			Data:              target.Data,
 			ChangeNote:        &changeNote,
 			CreatedBy:         stringPtrOrNil(userID),
+			AppVersion:        appmeta.Version(),
 		}
 
 		if err := tx.Create(version).Error; err != nil {

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
 }