i18n(alarm): localize all native notification, channel and chooser texts

Centralize every native-side user-facing string in a single
AlarmNotificationStrings store written by Flutter via a new
setNotificationStrings MethodChannel whenever the app locale changes,
and read at notification/channel build time (with English fallbacks)
even when the engine is dead. This replaces the hardcoded Spanish text
in the ringing notification ("Alarma PluriWave", "Posponer", "Detener"),
the pre-notice notification ("Posponer", "Omitir esta vez"), both
notification channels (names + descriptions) and the file-action
choosers ("Abrir carpeta", "Abrir grabación").

The per-alarm preNoticeTemplate/snoozeCountdown template+label args are
dropped from scheduleAlarm and the persisted spec and folded into the
shared store, so a locale change now also relocalizes already-scheduled
alarms. Channels are re-created on each use so their name/description
refresh after a language switch.

Adds alarmRingingNotificationTitle, alarmFire/PreNoticeChannelName,
alarmFire/PreNoticeChannelDescription and openFolder/openRecording
chooser keys across all 13 locales (reusing snoozeAction, stopAlarmAction,
skipNextAction, snoozeAgainAction). Rewrites the template test around
setNotificationStrings. Kotlin is static-reviewed only; no Android build
environment available here.

test/servicios/servicio_alarmas_pre_notice_template_test.dart

@@ -1,5 +1,8 @@
+import 'dart:ui' show Locale;
+
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:pluriwave/l10n/gen/app_localizations.dart';
 import 'package:pluriwave/modelos/alarma_musical.dart';
 import 'package:pluriwave/servicios/servicio_alarmas_android.dart';
 
@@ -25,55 +28,75 @@ void main() {
   });
 
   test(
-    'programar includes preNoticeTemplate with {minutes} placeholder in MethodChannel call',
+    'configurarLocalizaciones pushes localized notification strings with {minutes} templates',
     () async {
       final servicio = ServicioAlarmasAndroid(channel: channel);
-      final alarma = AlarmaMusical(
-        id: 'test-alarm',
-        nombre: 'Morning alarm',
-        hora: 7,
-        minuto: 0,
-        tipoProgramacion: TipoProgramacionAlarma.diaria,
-        diasSemana: const [],
-        proximaEjecucion: DateTime(2099, 1, 1, 7, 0),
+      final l10n = lookupAppLocalizations(const Locale('es'));
+
+      servicio.configurarLocalizaciones(l10n);
+      // configurarLocalizaciones fires setNotificationStrings as unawaited; let
+      // the microtask/event queue drain so the MethodChannel call is recorded.
+      await Future<void>.delayed(Duration.zero);
+
+      final llamada = llamadas.singleWhere(
+        (c) => c.method == 'setNotificationStrings',
+      );
+      final args = llamada.arguments as Map<Object?, Object?>;
+
+      expect(
+        args['preNoticeTemplate'],
+        contains('{minutes}'),
+        reason: 'pre-notice template must keep the {minutes} placeholder',
+      );
+      expect(
+        args['snoozeCountdownTemplate'],
+        contains('{minutes}'),
+        reason: 'snooze countdown template must keep the {minutes} placeholder',
       );
 
-      await servicio.programar(alarma);
-
-      final llamada = llamadas.singleWhere((c) => c.method == 'scheduleAlarm');
-      final args = llamada.arguments as Map<Object?, Object?>;
-      expect(args.containsKey('preNoticeTemplate'), isTrue,
-          reason: 'preNoticeTemplate must be present in scheduleAlarm args');
-      final template = args['preNoticeTemplate'] as String?;
-      expect(template, isNotNull,
-          reason: 'preNoticeTemplate must not be null');
-      expect(template, contains('{minutes}'),
-          reason: 'preNoticeTemplate must contain the {minutes} placeholder');
+      // Every notification/channel/chooser string must be present and non-empty
+      // so the native side never falls back to English for a configured locale.
+      const claves = [
+        'ringTitle',
+        'snoozeLabel',
+        'stopLabel',
+        'skipLabel',
+        'snoozeAgainLabel',
+        'fireChannelName',
+        'fireChannelDescription',
+        'preNoticeChannelName',
+        'preNoticeChannelDescription',
+        'openFolderTitle',
+        'openRecordingTitle',
+      ];
+      for (final clave in claves) {
+        expect(args[clave], isA<String>(), reason: '$clave missing');
+        expect(
+          (args[clave] as String).isNotEmpty,
+          isTrue,
+          reason: '$clave is empty',
+        );
+      }
     },
   );
 
-  test(
-    'programar preNoticeTemplate uses default locale fallback when no l10n configured',
-    () async {
-      // ServicioAlarmasAndroid falls back to es locale when no l10n is configured
-      final servicio = ServicioAlarmasAndroid(channel: channel);
-      final alarma = AlarmaMusical(
-        id: 'test-alarm-2',
-        nombre: 'Alarm',
-        hora: 8,
-        minuto: 30,
-        tipoProgramacion: TipoProgramacionAlarma.diaria,
-        diasSemana: const [],
-        proximaEjecucion: DateTime(2099, 1, 2, 8, 30),
-      );
+  test('scheduleAlarm no longer carries notification string templates', () async {
+    final servicio = ServicioAlarmasAndroid(channel: channel);
+    final alarma = AlarmaMusical(
+      id: 'no-template',
+      nombre: 'Alarm',
+      hora: 8,
+      minuto: 30,
+      tipoProgramacion: TipoProgramacionAlarma.diaria,
+      diasSemana: const [],
+      proximaEjecucion: DateTime(2099, 1, 2, 8, 30),
+    );
 
-      await servicio.programar(alarma);
+    await servicio.programar(alarma);
 
-      final llamada = llamadas.singleWhere((c) => c.method == 'scheduleAlarm');
-      final args = llamada.arguments as Map<Object?, Object?>;
-      final template = args['preNoticeTemplate'] as String?;
-      // The template must contain the literal placeholder string
-      expect(template, contains('{minutes}'));
-    },
-  );
+    final llamada = llamadas.singleWhere((c) => c.method == 'scheduleAlarm');
+    final args = llamada.arguments as Map<Object?, Object?>;
+    expect(args.containsKey('preNoticeTemplate'), isFalse);
+    expect(args.containsKey('snoozeCountdownTemplate'), isFalse);
+  });
 }