feat(shopping): Service-Worker network-only fuer /api/shopping-list/*

Einkaufsliste-Endpunkte duerfen vom SW nie gecached werden — Liste
ist zustaendig fuer Check-States und muss immer live vom Server
gelesen werden. Test + resolveStrategy-Erweiterung analog zu den
anderen online-only-Endpunkten.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/sw/cache-strategy.ts

@@ -17,7 +17,8 @@ export function resolveStrategy(req: RequestShape): CacheStrategy {
     path === '/api/recipes/import' ||
     path === '/api/recipes/preview' ||
     path === '/api/recipes/extract-from-photo' ||
-    path.startsWith('/api/recipes/search/web')
+    path.startsWith('/api/recipes/search/web') ||
+    path.startsWith('/api/shopping-list')
   ) {
     return 'network-only';
   }