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_resultado.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';
@@ -59,43 +60,46 @@ class _PantallaResultadoState extends State<PantallaResultado>
     final estado = context.read<EstadoJuego>();
     final partida = estado.partida;
 
-    return Scaffold(
-      appBar: AppBar(
-        title: Text(l10n.result),
-        automaticallyImplyLeading: false,
-      ),
-      body: FondoFarolero(
-        intenso: true,
-        respetarBarras: true,
-        child: Center(
-          child: SingleChildScrollView(
-            padding: const EdgeInsets.all(32),
-            child: Column(
-            mainAxisAlignment: MainAxisAlignment.center,
-            children: [
-              // Animación de suspense
-              if (!_revelado) ...[
-                const ArteGameplayFarolero.resultado(height: 152),
-                const SizedBox(height: 16),
-                Text(
-                  l10n.revealing,
-                  style: Theme.of(context).textTheme.headlineMedium,
-                ),
-                const SizedBox(height: 24),
-                const CircularProgressIndicator(color: TemaApp.colorAcento),
-              ],
-
-              if (_revelado) ...[
-                FadeTransition(
-                  opacity: _animOpacidad,
-                  child: ResultadoRondaFarolero(
-                    resultado: widget.resultado,
-                    jugadores: partida?.jugadores ?? const [],
-                    acciones: _construirBotones(context, estado),
+    return GuardiaSalidaPartida(
+      contexto: ContextoSalida.unDispositivo,
+      child: Scaffold(
+        appBar: AppBar(
+          title: Text(l10n.result),
+          automaticallyImplyLeading: false,
+        ),
+        body: FondoFarolero(
+          intenso: true,
+          respetarBarras: true,
+          child: Center(
+            child: SingleChildScrollView(
+              padding: const EdgeInsets.all(32),
+              child: Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: [
+                // Animación de suspense
+                if (!_revelado) ...[
+                  const ArteGameplayFarolero.resultado(height: 152),
+                  const SizedBox(height: 16),
+                  Text(
+                    l10n.revealing,
+                    style: Theme.of(context).textTheme.headlineMedium,
                   ),
-                ),
+                  const SizedBox(height: 24),
+                  const CircularProgressIndicator(color: TemaApp.colorAcento),
+                ],
+
+                if (_revelado) ...[
+                  FadeTransition(
+                    opacity: _animOpacidad,
+                    child: ResultadoRondaFarolero(
+                      resultado: widget.resultado,
+                      jugadores: partida?.jugadores ?? const [],
+                      acciones: _construirBotones(context, estado),
+                    ),
+                  ),
+                ],
               ],
-            ],
+              ),
             ),
           ),
         ),