fix: kiosk title center + location pref 2 uses + update confirm before download

app.js:
- _injectKioskOverlay: move kiosk-mode class assignment BEFORE the
  _kiosk_overlay existence guard — fixes race where Kotlin onPageFinished
  injects buttons during the await api() pause, then JS skips the class
- _PREF_LOC_NEEDED: 3 → 2 (remember use-location after 2 picks, not 3)

KioskActivity.kt:
- showNativeUpdateBanner: remove auto-start of triggerApkDownload;
  banner now shows with 'Scarica' button enabled, download only starts
  when user taps it (confirms before install)

assets/js/app.js

@@ -2025,12 +2025,14 @@ async function loadSettingsUI() {
 // Only shown when _kioskBridge JS interface is available (Android WebView).
 function _injectKioskOverlay() {
     if (typeof _kioskBridge === 'undefined') return;
-    if (document.getElementById('_kiosk_overlay')) return;
 
-    // Mark header so CSS can center the title
+    // Always mark header as kiosk-mode (idempotent) — must happen even if buttons
+    // were already injected by the native onPageFinished Kotlin callback.
     const appHeader = document.querySelector('.app-header');
     if (appHeader) appHeader.classList.add('kiosk-mode');
 
+    if (document.getElementById('_kiosk_overlay')) return;
+
     const headerLeft = document.getElementById('header-left');
     if (!headerLeft) return;
 
@@ -6869,7 +6871,7 @@ function selectUseLocation(btn, loc) {
 // After 3+ consistent choices from the same location for a product,
 // auto-selects it and hides the location picker (user can still tap "cambia").
 const _PREF_LOC_KEY = '_prefUseLoc';
-const _PREF_LOC_NEEDED = 3; // choices needed to confirm a preference
+const _PREF_LOC_NEEDED = 2; // choices needed to confirm a preference
 
 function _getPrefLocHistory(productId) {
     try {

evershelf-kiosk/app/src/main/kotlin/it/dadaloop/evershelf/kiosk/KioskActivity.kt

@@ -538,10 +538,11 @@ class KioskActivity : AppCompatActivity() {
     private fun showNativeUpdateBanner(message: String, apkDownloadUrl: String) {
         pendingApkDownloadUrl = apkDownloadUrl
         tvUpdateMessage.text = "⬆️ Aggiornamento disponibile:  $message"
+        // Reset button to initial state so user can confirm before download starts
+        btnInstallUpdate.isEnabled = true
+        btnInstallUpdate.text = "⬇ Scarica"
         updateBanner.visibility = View.VISIBLE
-        // Auto-start download immediately — no timer hide, stays until done or dismissed
+        // Download starts only when the user taps btnInstallUpdate
-        activeInstallBtn = btnInstallUpdate
-        triggerApkDownload(apkDownloadUrl)
     }
 
     // ── APK Download + Install ─────────────────────────────────────────────