fix(apk): coffre ferme, le champ du mot de passe de synchro dit qu'il est range dans le coffre

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

android-client/web/app.html

@@ -1677,7 +1677,7 @@ function openSettings() {
   var sp = document.getElementById('sPwd'),
       locked = (authMode === 'open' || authMode === 'login') && !vaultOpen;
   sp.disabled = locked;
-  sp.placeholder = locked ? 'sync password - open the vault to change it'
+  sp.placeholder = locked ? 'saved in the vault - open it to see or change it'
                           : 'sync password';
   cfgBase = cfgNow();
   syncSaveBtn(false);