feat: Phase 2 Schritt 11+12 — Essensplan-Modul + Einkaufslisten-Integration

- server/routes/meals.js: vollständige REST-API (GET Woche, POST/PUT/DELETE Mahlzeit,
  POST/PATCH/DELETE Zutaten, GET Autocomplete-Suggestions, POST to-shopping-list,
  POST week-to-shopping-list)
- public/pages/meals.js: Wochengitter (Mo–So × 4 Mahlzeit-Typen), Navigations-Buttons,
  CRUD-Modal mit Autocomplete, Zutaten-Verwaltung, Einkaufslisten-Transfer-Button
- public/styles/meals.css: Wochengitter, Slot-Karten, Modal-Overlay, Zutaten-Zeilen,
  Transfer-Panel, Typ-Farben
- test-meals.js: 22 Tests (CRUD, Wochensortierung, Constraint, CASCADE, Integration,
  Autocomplete, Wochenberechnung)
- package.json: test:meals + Gesamt-Test-Suite erweitert
- public/index.html: meals.css eingebunden

Gesamt: 93 Tests bestanden (29 DB + 8 Dashboard + 17 Tasks + 17 Shopping + 22 Meals)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/index.html

@@ -19,6 +19,7 @@
   <link rel="stylesheet" href="/styles/dashboard.css" />
   <link rel="stylesheet" href="/styles/tasks.css" />
   <link rel="stylesheet" href="/styles/shopping.css" />
+  <link rel="stylesheet" href="/styles/meals.css" />
 
   <!-- Lucide Icons (CDN) -->
   <script src="https://unpkg.com/lucide@latest/dist/umd/lucide.min.js"></script>