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/pantallas/pantalla_votacion.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import '../tema/dialogo_confirmacion.dart';
 import 'package:farolero/l10n/generated/app_localizations.dart';
 import 'package:provider/provider.dart';
 import '../estado/estado_juego.dart';
@@ -25,7 +26,12 @@ class _PantallaVotacionState extends State<PantallaVotacion> {
     final activos = partida.jugadoresActivos;
     final todosVotaron = estado.todosHanVotado();
 
-    return _construirVotacionUnMovil(context, estado, partida, activos, todosVotaron);
+    return GuardiaSalidaPartida(
+      contexto: ContextoSalida.unDispositivo,
+      child: _construirVotacionUnMovil(
+        context, estado, partida, activos, todosVotaron,
+      ),
+    );
   }
 
   Widget _construirVotacionUnMovil(