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/servicios/servicio_permisos.dart

@@ -1,4 +1,5 @@
 import 'dart:io';
+import 'package:farolero/l10n/generated/app_localizations.dart';
 import 'package:flutter/material.dart';
 import 'package:permission_handler/permission_handler.dart';
 
@@ -24,11 +25,14 @@ class ServicioPermisos {
     // Solicitar todos
     final resultados = await permisos.request();
 
+    if (!context.mounted) return false;
+    final l10n = AppLocalizations.of(context)!;
+
     // Verificar cuáles fueron denegados
     final denegados = <String>[];
     for (final entry in resultados.entries) {
       if (!entry.value.isGranted) {
-        denegados.add(_nombrePermiso(entry.key));
+        denegados.add(_nombrePermiso(entry.key, l10n));
       }
     }
 
@@ -39,20 +43,20 @@ class ServicioPermisos {
       final abrirConfig = await showDialog<bool>(
         context: context,
         builder: (ctx) => AlertDialog(
-          title: const Text('Permisos necesarios'),
+          title: Text(l10n.permissionsNeededTitle),
           content: Text(
-            'Para el modo multijugador necesitamos:\n\n'
+            '${l10n.permissionsNeededBody}\n\n'
             '${denegados.map((d) => '• $d').join('\n')}\n\n'
-            '¿Abrir configuración de la app?',
+            '${l10n.openAppSettingsQuestion}',
           ),
           actions: [
             TextButton(
               onPressed: () => Navigator.pop(ctx, false),
-              child: const Text('Cancelar'),
+              child: Text(l10n.cancel),
             ),
             TextButton(
               onPressed: () => Navigator.pop(ctx, true),
-              child: const Text('Abrir configuración'),
+              child: Text(l10n.openSettings),
             ),
           ],
         ),
@@ -66,12 +70,16 @@ class ServicioPermisos {
     return false;
   }
 
-  static String _nombrePermiso(Permission p) {
-    if (p == Permission.locationWhenInUse) return 'Ubicación';
-    if (p == Permission.bluetoothAdvertise) return 'Bluetooth (anunciar)';
-    if (p == Permission.bluetoothConnect) return 'Bluetooth (conectar)';
-    if (p == Permission.bluetoothScan) return 'Bluetooth (escanear)';
-    if (p == Permission.nearbyWifiDevices) return 'Wi-Fi cercano';
+  static String _nombrePermiso(Permission p, AppLocalizations l10n) {
+    if (p == Permission.locationWhenInUse) return l10n.permissionLocation;
+    if (p == Permission.bluetoothAdvertise) {
+      return l10n.permissionBluetoothAdvertise;
+    }
+    if (p == Permission.bluetoothConnect) {
+      return l10n.permissionBluetoothConnect;
+    }
+    if (p == Permission.bluetoothScan) return l10n.permissionBluetoothScan;
+    if (p == Permission.nearbyWifiDevices) return l10n.permissionNearbyWifi;
     return p.toString();
   }
 }