feat: confirm before leaving a game, and fix untranslated strings

Exit confirmation
- A dialog in the app's own style now guards every in-game screen. The safe
  action is the prominent one, so a stray tap keeps you in the game.
- Eleven screens covered, against both the system back gesture and the close
  buttons. The message adapts: a single-device game is lost, a host ends it
  for everyone, a client can rejoin.
- The two screens the host also opens from the manager take a flag so that
  back there just closes them instead of offering to quit.

Translations
- 21 keys were still holding the English text in Arabic, Basque, Hindi,
  Japanese, Korean, Dutch, Polish, Russian, Turkish and both Chinese
  variants: 231 strings, covering the whole multi-device flow, permissions
  and the mode picker. Nothing failed, the app just showed English.
- The permissions dialog was hardcoded in Spanish; it is localized now.
- Portuguese used Spanish gerunds where pt-PT takes "a + infinitive".

Checked what looked untranslated but is not: Animals and Notes are correct
Catalan, Configuration and Vibration correct French, Version correct German.
Those are whitelisted in the new test rather than silently rewritten.

l10n_cobertura_test guards all of it: no missing or orphan keys, no empty
values, no English left outside the whitelist, and placeholders preserved.

lib/l10n/generated/app_localizations_eu.dart

@@ -657,83 +657,83 @@ class AppLocalizationsEu extends AppLocalizations {
 
   @override
   String get selectAtLeastThreeUsersToStart =>
-      'Select at least 3 users to start.';
+      'Hautatu gutxienez 3 erabiltzaile hasteko.';
 
   @override
   String get hostPhoneMustSelectUser =>
-      'The host phone must select at least one user.';
+      'Ostalariaren mugikorrak gutxienez erabiltzaile bat hautatu behar du.';
 
   @override
-  String get roomNoLongerInLobby => 'The room is no longer in the lobby.';
+  String get roomNoLongerInLobby => 'Gela jada ez dago lobbyan.';
 
   @override
   String get completeUserSelectionToStart =>
-      'Complete user selection to start.';
+      'Osatu erabiltzaileen hautaketa hasteko.';
 
   @override
-  String get preparingSecureRoom => 'Preparing the secure room';
+  String get preparingSecureRoom => 'Gela segurua prestatzen';
 
   @override
   String get searchingNearbyBluetoothGames =>
-      'Searching nearby games over Bluetooth';
+      'Inguruko partidak bilatzen Bluetooth bidez';
 
   @override
-  String get tapToJoin => 'Tap to join';
+  String get tapToJoin => 'Sakatu batzeko';
 
   @override
   String get bluetoothLocationPermissionsRequired =>
-      'Bluetooth and location permissions are required to search for games.';
+      'Bluetooth eta kokapen baimenak behar dira partidak bilatzeko.';
 
   @override
   String get bluetoothLocationPermissionsShort =>
-      'Bluetooth and location permissions are required';
+      'Bluetooth eta kokapen baimenak behar dira';
 
   @override
   String get couldNotStartSearch =>
-      'Could not start the search. Check Bluetooth and location.';
+      'Ezin izan da bilaketa hasi. Egiaztatu Bluetooth eta kokapena.';
 
   @override
   String couldNotConnectToHost(String host) {
-    return 'Could not connect to $host';
+    return 'Ezin izan da $host(e)ra konektatu';
   }
 
   @override
   String get room => 'Gela';
 
   @override
-  String get singleDeviceSubtitle => 'Game on this device';
+  String get singleDeviceSubtitle => 'Partida gailu honetan';
 
   @override
   String get singleDeviceDescription =>
-      'Ideal for playing together by passing the phone around. Fast, direct setup.';
+      'Ezin hobea denok elkarrekin jokatzeko mugikorra pasatuz. Konfigurazio azkarra eta zuzena.';
 
   @override
-  String get multiDeviceSubtitle => 'Each player on their phone';
+  String get multiDeviceSubtitle => 'Jokalari bakoitza bere mugikorrean';
 
   @override
   String get multiDeviceDescription =>
-      'Create a premium room, share the QR code and manage users from the lobby.';
+      'Sortu gela premium bat, partekatu QR kodea eta kudeatu erabiltzaileak lobbytik.';
 
   @override
-  String get singleDeviceGameLabel => 'Game on this device';
+  String get singleDeviceGameLabel => 'Partida gailu honetan';
 
   @override
-  String get multiDeviceGameLabel => 'Multi-device game';
+  String get multiDeviceGameLabel => 'Gailu anitzeko partida';
 
   @override
-  String get mainDeviceUser => 'Main device user';
+  String get mainDeviceUser => 'Gailuaren erabiltzaile nagusia';
 
   @override
   String get couldNotCreateRoom =>
-      'Could not create the room. Check Bluetooth.';
+      'Ezin izan da gela sortu. Egiaztatu Bluetooth.';
 
   @override
   String cannotStartWithReason(String reason) {
-    return 'Cannot start: $reason';
+    return 'Ezin da hasi: $reason';
   }
 
   @override
-  String get invalidRoom => 'invalid room';
+  String get invalidRoom => 'gela baliogabea';
 
   @override
   String get defaultPlayerName => 'Jokalaria';
@@ -847,4 +847,51 @@ class AppLocalizationsEu extends AppLocalizations {
   String playerRejoined(String name) {
     return '$name partidara itzuli da';
   }
+
+  @override
+  String get leaveGameTitle => 'Partidatik irten nahi duzu?';
+
+  @override
+  String get leaveGameSingleDevice =>
+      'Abian den partida galduko da eta ezin izango duzu berreskuratu.';
+
+  @override
+  String get leaveGameHost =>
+      'Zu zara ostalaria: irtenez gero, partida jokalari guztientzat amaituko da.';
+
+  @override
+  String get leaveGameClient =>
+      'Partidatik aterako zara. Itzuli ahal izango zara ostalariak zabalik mantentzen duen bitartean.';
+
+  @override
+  String get stayInGame => 'Jokatzen jarraitu';
+
+  @override
+  String get permissionsNeededTitle => 'Baimenak behar dira';
+
+  @override
+  String get permissionsNeededBody =>
+      'Jokalari anitzeko modurako hau behar dugu:';
+
+  @override
+  String get openAppSettingsQuestion =>
+      'Aplikazioaren ezarpenak ireki nahi dituzu?';
+
+  @override
+  String get openSettings => 'Ireki ezarpenak';
+
+  @override
+  String get permissionLocation => 'Kokapena';
+
+  @override
+  String get permissionBluetoothAdvertise => 'Bluetooth (iragarri)';
+
+  @override
+  String get permissionBluetoothConnect => 'Bluetooth (konektatu)';
+
+  @override
+  String get permissionBluetoothScan => 'Bluetooth (eskaneatu)';
+
+  @override
+  String get permissionNearbyWifi => 'Inguruko Wi-Fi';
 }