fix(alarm): unfreeze snooze modal and add per-minute snooze countdown

The snooze button was fire-and-forget without error handling: if
posponerAlarma threw (e.g. native scheduleAlarm returns false on a
device without exact-alarm permission), _dismissScreen never ran. The
stuck modal also kept _alarmaSonandoActiva true, which made the next
ring get ignored. _posponer/_detener now dismiss in a finally and stop
audio defensively.

Add a native, AlarmManager-driven snooze countdown notification that
re-posts every minute ("Rings in N min", 3->2->1) while the engine is
dead. scheduleSpec drives scheduleSnoozeCountdown for snoozes (instead
of the 30-min pre-notice). Localized text and button labels travel
Dart->Kotlin as {minutes} templates, same pattern as preNoticeTemplate.

Notification actions: "snooze again" (snoozeAgain, anchored to now)
reports back via the existing snoozed event; "stop" (cancelSnooze)
records a handled occurrence for cold-start reconciliation and emits a
new snoozeCancelled event handled in EstadoAlarmas.

Adds snoozeCountdown/snoozeAgainAction keys across all 13 locales and a
test for the snoozeCancelled event. Kotlin changes are static-reviewed
only; no Android build environment available here.

lib/estado/estado_alarmas.dart

@@ -281,6 +281,10 @@ class EstadoAlarmas extends ChangeNotifier {
   /// The native scheduler already re-registered setAlarmClock, so this only
   /// persists the canonical state — it MUST NOT call android.programar again.
   Future<void> _alRecibirEventoNativo(EventoAlarmaAndroid evento) async {
+    if (evento.accion == EventoAlarmaAndroid.accionSnoozeCancelled) {
+      await _registrarCancelacionSnoozeNativa(evento);
+      return;
+    }
     if (evento.accion != EventoAlarmaAndroid.accionSnoozed) return;
     if (evento.alarmaId.isEmpty || evento.snoozeUntilMillis <= 0) return;
     final hasta = DateTime.fromMillisecondsSinceEpoch(evento.snoozeUntilMillis);
@@ -304,6 +308,30 @@ class EstadoAlarmas extends ChangeNotifier {
     }
   }
 
+  /// Mirrors a native snooze cancellation ("Detener" on the countdown
+  /// notification). The native scheduler already advanced to the next normal
+  /// occurrence, so this only clears the snooze in the canonical config and
+  /// MUST NOT call android.programar again (would double-schedule).
+  Future<void> _registrarCancelacionSnoozeNativa(
+    EventoAlarmaAndroid evento,
+  ) async {
+    if (evento.alarmaId.isEmpty) return;
+    final origen =
+        evento.occurrenceAtMillis > 0
+            ? DateTime.fromMillisecondsSinceEpoch(evento.occurrenceAtMillis)
+            : DateTime.now();
+    debugPrint(
+      '[PluriWave][alarmas] snooze cancelado nativo id=${evento.alarmaId} origen=${origen.toIso8601String()}',
+    );
+    try {
+      final config = await servicio.completarEjecucion(evento.alarmaId, origen);
+      _aplicar(config);
+      notifyListeners();
+    } catch (e) {
+      debugPrint('[PluriWave][alarmas] cancelar snooze nativo ERROR $e');
+    }
+  }
+
   Future<void> _sincronizarEjecucionesGestionadasPorAndroid() async {
     try {
       final ejecuciones = await android.obtenerEjecucionesNativasGestionadas();