Enhance syncModelsAlways function to handle problematic ENUM changes

- Added logic to skip synchronization for specific tables with known ENUM issues, improving stability during model synchronization.
- Restored associations and virtual fields for models when skipping sync, ensuring data integrity and consistency.

backend/utils/sequelize.js

@@ -695,6 +695,22 @@ const syncModelsAlways = async (models) => {
                         continue;
                     }
                     
+                    // Für Tabellen mit problematischen ENUM-Änderungen - wenn Tabelle existiert, überspringe Sync
+                    // Sequelize generiert fehlerhaftes SQL bei ENUM-Änderungen mit Kommentaren
+                    const enumProblemTables = ['TaxiMapTileHouse'];
+                    if (enumProblemTables.includes(model.name) && tableExists) {
+                        console.log(`  ℹ️  ${model.name} Tabelle existiert bereits - überspringe Sync (ENUM-Änderungen problematisch)`);
+                        // Restore associations before continuing
+                        if (associationKeys.length > 0) {
+                            model.associations = originalAssociations;
+                        }
+                        // Restore virtual fields
+                        for (const [key, attr] of Object.entries(virtualFields)) {
+                            model.rawAttributes[key] = attr;
+                        }
+                        continue;
+                    }
+                    
                     // Verwende syncModelWithTimeout für große Tabellen
                     const syncSuccess = await syncModelWithTimeout(model, 60000);
                     if (!syncSuccess) {