fix: restore app.js after sed truncation, update nav title to EverShelf

- Recover app.js from pre-rebrand commit and re-apply all substitutions safely
- Fix all localStorage keys: dispensa_* -> evershelf_* (settings, setup, lang)
- Fix TTS test strings: 'Dispensa Manager' -> 'EverShelf'
- Set nav.title to EverShelf in it/en/de translations and HTML fallback
- Fix JS syntax error (Unexpected end of input) that broke the site
- CI JavaScript Lint should now pass

translations/de.json

@@ -4,7 +4,7 @@
     "loading": "Laden..."
   },
   "nav": {
-    "title": "🏠 Vorratskammer",
+    "title": "🏠 EverShelf",
     "home": "Home",
     "inventory": "Vorrat",
     "recipes": "Rezepte",