Add vehicle repair functionality in Falukant module

- Implemented a new repairVehicle method in FalukantService to handle vehicle repairs, including cost calculation and precondition checks.
- Updated FalukantController to expose the repairVehicle endpoint, allowing users to initiate repairs via the API.
- Enhanced FalukantRouter to include a new route for vehicle repairs.
- Modified BranchView component to add UI elements for repairing vehicles, including a dialog for repair confirmation and displaying repair details.
- Updated German localization files to include translations related to vehicle repair actions, improving user experience for German-speaking users.

backend/utils/syncDatabase.js

@@ -133,6 +133,45 @@ const syncDatabaseForDeployment = async () => {
             console.warn('⚠️  Konnte traffic_light-Spalte nicht vorab sicherstellen:', e?.message || e);
         }
 
+        // Migration: Transport product_id und size nullable machen
+        console.log("Making transport product_id and size nullable...");
+        try {
+            await sequelize.query(`
+                DO $$
+                BEGIN
+                    -- Prüfe ob product_id NOT NULL Constraint existiert
+                    IF EXISTS (
+                        SELECT 1 FROM information_schema.columns
+                        WHERE table_schema = 'falukant_data' 
+                        AND table_name = 'transport' 
+                        AND column_name = 'product_id'
+                        AND is_nullable = 'NO'
+                    ) THEN
+                        ALTER TABLE falukant_data.transport 
+                        ALTER COLUMN product_id DROP NOT NULL;
+                        RAISE NOTICE 'product_id NOT NULL Constraint entfernt';
+                    END IF;
+                    
+                    -- Prüfe ob size NOT NULL Constraint existiert
+                    IF EXISTS (
+                        SELECT 1 FROM information_schema.columns
+                        WHERE table_schema = 'falukant_data' 
+                        AND table_name = 'transport' 
+                        AND column_name = 'size'
+                        AND is_nullable = 'NO'
+                    ) THEN
+                        ALTER TABLE falukant_data.transport 
+                        ALTER COLUMN size DROP NOT NULL;
+                        RAISE NOTICE 'size NOT NULL Constraint entfernt';
+                    END IF;
+                END
+                $$;
+            `);
+            console.log("✅ Transport product_id und size sind jetzt nullable");
+        } catch (e) {
+            console.warn('⚠️  Konnte Transport-Spalten nicht nullable machen:', e?.message || e);
+        }
+
         console.log("Setting up associations...");
         setupAssociations();