feat: add separate sound beep test button + always show move modal on open

- Add testSound() function: plays AudioContext beep independently of TTS
- Add '🔔 Esegui Test Suono' button in TTS settings (above voice test btn)
- Add translations: settings.tts.test_sound_btn (it/en/de)
- Remove hasOtherLocs guard in showMoveAfterUseModal: always show
  location-choice modal when opening a package, regardless of whether
  the product already exists in other locations (e.g. peas only in pantry
  → user can now choose to move opened portion to fridge)

index.html

@@ -1314,6 +1314,7 @@
                     </div>
                     </div><!-- /tts-server-section -->
 
+                    <button class="btn btn-large btn-secondary full-width mt-2" onclick="testSound()" data-i18n="settings.tts.test_sound_btn">🔔 Esegui Test Suono</button>
                     <button class="btn btn-large btn-accent full-width mt-2" onclick="testTTS()" data-i18n="settings.tts.test_btn">🔊 Invia Test Vocale</button>
                     <div id="tts-test-status" style="display:none;margin-top:8px"></div>
                     <!-- HA TTS quick-fill hint -->