fix(alarmas): decode native failures with the real channel key names

The first pass read 'alarmaId'/'tipo' from the channel payload while the
native side sends 'alarmId'/'type'/'atMillis' (AlarmScheduler.kt:1389).
Every entry would have been dropped silently in production.

The tests passed because the fake was seeded with the same guessed keys,
so they confirmed the mistake instead of catching it. Decoding now goes
through FalloProgramacionNativo.fromMap -- the single place native key
names appear -- and the fixtures build through that same constructor.

lib/estado/estado_alarmas.dart

@@ -556,10 +556,7 @@ class EstadoAlarmas extends ChangeNotifier {
     try {
       final fallos = await android.fallosNativosProgramacion();
       for (final fallo in fallos) {
-        final alarmaId = fallo['alarmaId'] as String?;
-        final tipo = fallo['tipo'] as String?;
-        if (alarmaId == null || tipo == null) continue;
-        await _registrarFalloProgramacion(alarmaId, tipo: tipo);
+        await _registrarFalloProgramacion(fallo.alarmaId, tipo: fallo.tipo);
       }
       if (fallos.isNotEmpty) {
         debugPrint(