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

index.html

@@ -20,7 +20,7 @@
 <!-- Top Header -->
 <header class="app-header">
     <div class="header-content">
-        <h1 class="header-title" onclick="showPage('dashboard')" data-i18n="nav.title">🏠 Dispensa</h1>
+        <h1 class="header-title" onclick="showPage('dashboard')" data-i18n="nav.title">🏠 EverShelf</h1>
         <div class="header-actions">
             <button class="header-scan-btn header-gemini-btn" onclick="showPage('chat')" title="Chat con Gemini" data-i18n-title="chat.title">
                 <svg class="gemini-icon" viewBox="0 0 24 24" width="28" height="28" fill="white"><path d="M12 0C12 6.627 6.627 12 0 12c6.627 0 12 5.373 12 12 0-6.627 5.373-12 12-12-6.627 0-12-5.373-12-12z"/></svg>