feat(iap): add freemium unlock via one-time in-app purchase

Adds a permanent, non-consumable premium unlock (EstadoEntitlement +
PuertoCompras/ServicioComprasPlayBilling) that removes ads and unlocks
alarm vacations, alarms past a 5-alarm free cap, recording start, and
full Android Auto browsing. The phone equalizer stays free for everyone.

- Entitlement is prefs-backed (compra_premium_v1), fail-open, and
  resolvable headlessly via esPremiumPersistido() for the Android Auto
  audio handler, which registers before runApp.
- Android Auto reduced mode keeps the real root folder labels for free
  users; browsing into any of them (and playFromMediaId/playFromSearch/
  skipToNext/skipToPrevious) is blocked at the getChildren/servicio_audio
  choke points, with a locked "Función Premium" item as the backstop.
  Current-station play/pause/stop stays untouched. A free -> premium
  transition actively invalidates the head unit's cached browse tree.
- Ads (top banner + capped interstitial before adding a station or an
  alarm) are gated behind entitlement via ServicioAnuncios, using
  official Google test ad unit IDs pending AdMob provisioning.
- Alarm cap UX shows an explanatory message with a secondary unlock
  action rather than a bare paywall jump; existing data is grandfathered.
- 4 new localization keys translated across all 13 supported locales.

Co-located tests use strict TDD (RED test before implementation) for
every new pure-logic unit; full existing suite passes unchanged.

lib/app.dart

@@ -4,11 +4,15 @@ import 'package:provider/provider.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'estado/estado_busqueda.dart';
 import 'estado/estado_ecualizador.dart';
+import 'estado/estado_entitlement.dart';
 import 'estado/estado_grabacion.dart';
 import 'estado/estado_radio.dart';
 import 'estado/estado_alarmas.dart';
 import 'estado/estado_idioma.dart';
 import 'estado/estado_navegacion.dart';
+import 'servicios/servicio_anuncios.dart';
+import 'servicios/servicio_compras.dart';
+import 'widgets/banner_anuncio_superior.dart';
 import 'l10n/display_names.dart';
 import 'l10n/gen/app_localizations.dart';
 import 'modelos/alarma_musical.dart';
@@ -32,7 +36,7 @@ import 'servicios/servicio_alarmas_android.dart';
 import 'servicios/servicio_dispositivo_audio.dart';
 
 class PluriWaveApp extends StatelessWidget {
-  const PluriWaveApp({super.key, this.prefs, this.fuenteAuto});
+  const PluriWaveApp({super.key, this.prefs, this.fuenteAuto, this.compras});
 
   /// Single SharedPreferences instance resolved in main() (S3-R4) and
   /// injected into every state/service.
@@ -44,16 +48,31 @@ class PluriWaveApp extends StatelessWidget {
   /// [PluriWaveApp] without it.
   final FuenteEmisorasAuto? fuenteAuto;
 
+  /// Purchase I/O port (iap-freemium-unlock, Design ADR-2). Optional and
+  /// `null` by default — mirrors [fuenteAuto]'s injection shape, so every
+  /// pre-existing test that constructs [PluriWaveApp] without it never
+  /// touches the real `in_app_purchase` plugin channel. `main.dart` wires
+  /// the real [ServicioComprasPlayBilling].
+  final PuertoCompras? compras;
+
   @override
   Widget build(BuildContext context) {
     return MultiProvider(
       providers: [
+        // iap-freemium-unlock (Design ADR-3): registered FIRST so every
+        // provider below can read it via `context.read` inside a lazy
+        // `esPremium` closure — `MultiProvider` nests top-to-bottom, so only
+        // a provider ABOVE a given one is reachable from its own `create`.
+        ChangeNotifierProvider(
+          create: (_) => EstadoEntitlement(prefs: prefs, compras: compras),
+        ),
         ChangeNotifierProvider(
           create:
-              (_) => EstadoRadio(
+              (context) => EstadoRadio(
                 prefs: prefs,
                 dispositivoAudio: ServicioDispositivoAudioReal(),
                 fuenteAuto: fuenteAuto,
+                esPremium: () => context.read<EstadoEntitlement>().esPremium,
               ),
         ),
         // Domain notifiers (S4-R1/R2/R3). Created and disposed by EstadoRadio
@@ -69,13 +88,28 @@ class PluriWaveApp extends StatelessWidget {
         ListenableProvider<EstadoBusqueda>(
           create: (context) => context.read<EstadoRadio>().busqueda,
         ),
-        ChangeNotifierProvider(create: (_) => EstadoAlarmas(prefs: prefs)),
+        ChangeNotifierProvider(
+          create:
+              (context) => EstadoAlarmas(
+                prefs: prefs,
+                esPremium: () => context.read<EstadoEntitlement>().esPremium,
+              ),
+        ),
         ChangeNotifierProvider(
           create: (_) => EstadoIdioma(sharedPreferences: prefs),
         ),
         // Design ADR-8: root-to-root navigation state. `_PaginaPrincipal`
         // watches this instead of owning `_indice` locally.
         ChangeNotifierProvider(create: (_) => EstadoNavegacionRaiz()),
+        // iap-freemium-unlock (Design "Interfaces / Contracts", ADR-6): a
+        // plain (non-notifier) `Provider` — session-scoped ad state, never
+        // rebuilds the widget tree itself.
+        Provider<ServicioAnuncios>(
+          create:
+              (context) => ServicioAnuncios(
+                esPremium: () => context.read<EstadoEntitlement>().esPremium,
+              ),
+        ),
       ],
       child: Consumer<EstadoIdioma>(
         builder:
@@ -218,28 +252,40 @@ class _PaginaPrincipalState extends State<_PaginaPrincipal>
     final indice = navegacion.indice;
 
     return PluriWaveScaffold(
-      body: SafeArea(
-        top: false,
-        child: AnimatedSwitcher(
-          duration: context.pluriMotion.normal,
-          switchInCurve: Curves.easeOutCubic,
-          switchOutCurve: Curves.easeInCubic,
-          transitionBuilder:
-              (child, animation) => FadeTransition(
-                opacity: animation,
-                child: SlideTransition(
-                  position: Tween<Offset>(
-                    begin: const Offset(0.035, 0),
-                    end: Offset.zero,
-                  ).animate(animation),
-                  child: child,
+      // ad-display spec "Persistent Top Banner, Never Overlapping Content"
+      // (design.md ADR-6): a `Column` sibling, NEVER a `Stack`/overlay — the
+      // banner RESERVES its own space above the existing body instead of
+      // covering any of it. `BannerAnuncioSuperior` itself collapses to
+      // `SizedBox.shrink()` (zero layout impact) for premium/unloaded.
+      body: Column(
+        children: [
+          const SafeArea(bottom: false, child: BannerAnuncioSuperior()),
+          Expanded(
+            child: SafeArea(
+              top: false,
+              child: AnimatedSwitcher(
+                duration: context.pluriMotion.normal,
+                switchInCurve: Curves.easeOutCubic,
+                switchOutCurve: Curves.easeInCubic,
+                transitionBuilder:
+                    (child, animation) => FadeTransition(
+                      opacity: animation,
+                      child: SlideTransition(
+                        position: Tween<Offset>(
+                          begin: const Offset(0.035, 0),
+                          end: Offset.zero,
+                        ).animate(animation),
+                        child: child,
+                      ),
+                    ),
+                child: KeyedSubtree(
+                  key: ValueKey<int>(indice),
+                  child: _paginas[indice],
                 ),
               ),
-          child: KeyedSubtree(
-            key: ValueKey<int>(indice),
-            child: _paginas[indice],
+            ),
           ),
-        ),
+        ],
       ),
       bottomNavigationBar: SafeArea(
         top: false,

lib/estado/estado_alarmas.dart

@@ -9,15 +9,31 @@ import '../servicios/servicio_alarmas.dart';
 import '../servicios/servicio_alarmas_android.dart';
 import '../servicios/servicio_programacion_alarmas.dart';
 
+/// Distinct "limit reached" signal (Design ADR-5, freemium-gating spec
+/// "Alarm Count Cap At 5"): kept SEPARATE from [EstadoAlarmas.error], which
+/// stays reserved for native scheduling failures — overloading it would
+/// surface a free-tier limit as a scheduling failure in `app.dart`'s global
+/// snackbar path.
+enum ResultadoGuardarAlarma { guardada, limiteAlcanzado }
+
 class EstadoAlarmas extends ChangeNotifier {
   EstadoAlarmas({
     ServicioAlarmas? servicio,
     PuertoAlarmasAndroid? android,
     SharedPreferences? prefs,
     bool iniciarAutomaticamente = true,
+    // iap-freemium-unlock (Design ADR-3): entitlement query, mirroring
+    // `EstadoGrabacion`'s `emisoraActual` callback-injection shape rather
+    // than a direct `EstadoEntitlement` dependency (this notifier must stay
+    // constructible with zero widget-tree/Provider context). Defaults to
+    // "premium" (ungated) so every pre-existing test/call site that never
+    // wires entitlement keeps its exact previous behavior — production
+    // wiring in `app.dart` always passes the real callback.
+    bool Function()? esPremium,
   }) : servicio = servicio ?? ServicioAlarmas(prefs: prefs),
        android = android ?? ServicioAlarmasAndroid(),
-       _prefs = prefs {
+       _prefs = prefs,
+       _esPremium = esPremium ?? (() => true) {
     // Decision 2.1 (snooze sync): the native layer reports its own snoozes
     // back through alarmFired/snoozed; record them here so the Flutter
     // config stays the single source of truth.
@@ -32,8 +48,12 @@ class EstadoAlarmas extends ChangeNotifier {
   final ServicioAlarmas servicio;
   final PuertoAlarmasAndroid android;
   final SharedPreferences? _prefs;
+  final bool Function() _esPremium;
   static const _keyExencionBateriaSolicitada = 'bateria_exencion_solicitada';
 
+  /// Free-tier alarm cap (freemium-gating spec "Alarm Count Cap At 5").
+  static const maxAlarmasFree = 5;
+
   List<AlarmaMusical> _alarmas = [];
   List<RangoVacaciones> _vacaciones = [];
   List<ExcepcionAlarma> _excepciones = [];
@@ -101,7 +121,26 @@ class EstadoAlarmas extends ChangeNotifier {
     }
   }
 
-  Future<void> guardarAlarma(AlarmaMusical alarma) async {
+  /// Pure query (freemium-gating spec "Alarm Count Cap At 5"): whether a NEW
+  /// alarm may be created right now. Counts ALL alarms regardless of
+  /// `activa` (Spec "6th alarm creation is blocked" — "any enabled state").
+  /// Always `true` for premium (no cap). Editing an existing id is never
+  /// subject to this — see [guardarAlarma]'s own new-vs-edit check.
+  bool puedeCrearAlarma() => _esPremium() || _alarmas.length < maxAlarmasFree;
+
+  Future<ResultadoGuardarAlarma> guardarAlarma(AlarmaMusical alarma) async {
+    // Gate BEFORE any native scheduling attempt (freemium-gating spec "6th
+    // alarm creation is blocked": "no native scheduling is attempted").
+    // Editing an alarm that already exists (by id) is NEVER capped — only
+    // genuinely NEW creation counts against the limit (Spec "Editing an
+    // existing alarm is unaffected", grandfathering).
+    final esAlarmaNueva = !_alarmas.any((a) => a.id == alarma.id);
+    if (esAlarmaNueva && !puedeCrearAlarma()) {
+      debugPrint(
+        '[PluriWave][alarmas] guardar bloqueado por limite free id=${alarma.id}',
+      );
+      return ResultadoGuardarAlarma.limiteAlcanzado;
+    }
     debugPrint(
       '[PluriWave][alarmas] guardar id=${alarma.id} activa=${alarma.activa} hora=${alarma.hora}:${alarma.minuto} tipo=${alarma.tipoProgramacion.name}',
     );
@@ -125,6 +164,7 @@ class EstadoAlarmas extends ChangeNotifier {
       await _registrarFalloProgramacion(alarma.id);
     }
     notifyListeners();
+    return ResultadoGuardarAlarma.guardada;
   }
 
   Future<void> refrescarProgramacion() async {
@@ -507,9 +547,20 @@ class EstadoAlarmas extends ChangeNotifier {
     notifyListeners();
   }
 
-  Future<void> crearRangoVacaciones(RangoVacaciones rango) async {
+  /// Full premium gate (freemium-gating spec "Gated Feature Set (Exactly
+  /// 4)" — alarm vacations, unlike the alarm cap above, are gated entirely,
+  /// not counted): returns `false` without persisting anything when the
+  /// caller is free tier.
+  Future<bool> crearRangoVacaciones(RangoVacaciones rango) async {
+    if (!_esPremium()) {
+      debugPrint(
+        '[PluriWave][alarmas] crear vacaciones bloqueado (free) id=${rango.id}',
+      );
+      return false;
+    }
     final nuevos = [..._vacaciones, rango];
     await guardarVacaciones(nuevos);
+    return true;
   }
 
   Future<void> eliminarRangoVacaciones(String id) async {

lib/estado/estado_entitlement.dart

@@ -0,0 +1,140 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import '../servicios/servicio_audio.dart' show notificarDesbloqueoAuto;
+import '../servicios/servicio_compras.dart';
+
+/// Versioned persistence key (Design ADR-1) for the permanent, non-consumable
+/// premium unlock. Older builds that predate this key simply never read it —
+/// no migration needed (Rollout "Versioned key ... is ignored by older
+/// builds").
+const _keyPremium = 'compra_premium_v1';
+
+/// Headless-safe entitlement read (Design ADR-1, Spec "Headless-Safe
+/// Entitlement Read"): resolves the persisted premium flag directly from
+/// prefs, with NO `BuildContext`/`Provider` dependency. Mirrors
+/// `FuenteMusicaLocalAutoImpl._resolverPrefs()`'s
+/// inject-or-`getInstance()` convention (`musica_local_auto.dart:163`) —
+/// this is what `PluriWaveAudioHandler` calls, since it registers before
+/// `runApp` and no widget tree (therefore no `Provider`) exists yet.
+///
+/// Absent key = free tier (Rollout "Additive and prefs-backed; absent key =
+/// free"). Never throws — a `SharedPreferences.getInstance()` failure would
+/// propagate here exactly like the persisted read failing, which the caller
+/// (Design ADR-2 "fail-open") must treat as "trust the last known state",
+/// not this function's job to catch.
+Future<bool> esPremiumPersistido({SharedPreferences? prefs}) async {
+  final resueltas = prefs ?? await SharedPreferences.getInstance();
+  return resueltas.getBool(_keyPremium) ?? false;
+}
+
+/// Cross-cutting entitlement notifier (Design ADR-1), idiomatic
+/// `EstadoIdioma`-shaped `ChangeNotifier`: UI layers `context.watch`/`read`
+/// this; headless callers (Android Auto) use [esPremiumPersistido] instead,
+/// since no `Provider` exists on that path.
+class EstadoEntitlement extends ChangeNotifier {
+  EstadoEntitlement({SharedPreferences? prefs, PuertoCompras? compras})
+    : _prefs = prefs,
+      _compras = compras {
+    final flujo = _compras;
+    if (flujo != null) {
+      _comprasSub = flujo.eventos.listen(_alRecibirEvento);
+    }
+    _cargar();
+  }
+
+  /// The single non-consumable product id (Design "Interfaces / Contracts"),
+  /// re-exported here so UI/paywall code depends on ONE canonical constant
+  /// rather than reaching into `servicio_compras.dart` for it.
+  static const idProducto = ServicioComprasPlayBilling.idProducto;
+
+  final SharedPreferences? _prefs;
+  final PuertoCompras? _compras;
+  StreamSubscription<EventoCompra>? _comprasSub;
+
+  bool _esPremium = false;
+  bool _compraEnCurso = false;
+
+  bool get esPremium => _esPremium;
+  bool get compraEnCurso => _compraEnCurso;
+
+  Future<void> _cargar() async {
+    final prefs = await _resolverPrefs();
+    final premium = prefs.getBool(_keyPremium) ?? false;
+    if (premium != _esPremium) {
+      _esPremium = premium;
+    }
+    notifyListeners();
+  }
+
+  Future<SharedPreferences> _resolverPrefs() async =>
+      _prefs ?? SharedPreferences.getInstance();
+
+  /// Starts the purchase flow (Spec "Successful purchase"). A no-op when
+  /// already premium (Spec "Already-purchased attempt is idempotent") — no
+  /// duplicate charge is even attempted.
+  Future<void> comprar() async {
+    if (_esPremium) return;
+    final compras = _compras;
+    if (compras == null) return;
+    _compraEnCurso = true;
+    notifyListeners();
+    await compras.comprar();
+  }
+
+  /// Re-queries Play Billing for a prior purchase (Spec "Restore Purchases").
+  Future<void> restaurar() async {
+    final compras = _compras;
+    if (compras == null) return;
+    _compraEnCurso = true;
+    notifyListeners();
+    await compras.restaurar();
+  }
+
+  Future<void> _alRecibirEvento(EventoCompra evento) async {
+    switch (evento.tipo) {
+      case TipoEventoCompra.comprada:
+      case TipoEventoCompra.restaurada:
+        await _desbloquear();
+      case TipoEventoCompra.cancelada:
+      case TipoEventoCompra.noEncontrada:
+        // Spec "Purchase cancelled or failed" / "Restore finds nothing":
+        // stays free tier, no error surfaced — just stop the in-flight
+        // spinner.
+        _compraEnCurso = false;
+        notifyListeners();
+      case TipoEventoCompra.error:
+        // Fail-open (Design ADR-2): an error NEVER writes `false` over an
+        // already-premium flag, and never invents a `true` for a free user
+        // either — the persisted flag from `_cargar()` is left untouched.
+        _compraEnCurso = false;
+        notifyListeners();
+      case TipoEventoCompra.pendiente:
+        _compraEnCurso = true;
+        notifyListeners();
+    }
+  }
+
+  Future<void> _desbloquear() async {
+    final yaEraPremium = _esPremium;
+    _esPremium = true;
+    _compraEnCurso = false;
+    final prefs = await _resolverPrefs();
+    await prefs.setBool(_keyPremium, true);
+    notifyListeners();
+    if (!yaEraPremium) {
+      // Orchestrator-resolved open question (design.md): actively
+      // invalidate the Android Auto browse cache on the free -> premium
+      // transition, rather than waiting for the head unit's own re-bind.
+      notificarDesbloqueoAuto();
+    }
+  }
+
+  @override
+  void dispose() {
+    _comprasSub?.cancel();
+    super.dispose();
+  }
+}

lib/estado/estado_grabacion.dart

@@ -35,14 +35,26 @@ bool esEmisoraGrabable(Emisora emisora) {
   return esquema == 'http' || esquema == 'https';
 }
 
+/// Distinct outcome signal for [EstadoGrabacion.iniciar] (freemium-gating
+/// spec "Recording Start Gated"): [requierePremium] is NOT surfaced through
+/// [EstadoGrabacion.iniciar]'s existing `alError` sink — the caller must
+/// react by opening the paywall, a different UI than a plain error snackbar.
+enum ResultadoIniciarGrabacion { iniciada, requierePremium, error }
+
 class EstadoGrabacion extends ChangeNotifier {
   EstadoGrabacion({
     ServicioGrabacionRadio? servicio,
     Emisora? Function()? emisoraActual,
     void Function(String mensaje)? alError,
+    // iap-freemium-unlock (Design ADR-3): entitlement query, mirroring
+    // [_emisoraActual]'s callback-injection shape. Defaults to "premium"
+    // (ungated) so every pre-existing test/call site keeps its exact
+    // previous behavior — `app.dart` always wires the real callback.
+    bool Function()? esPremium,
   }) : servicio = servicio ?? ServicioGrabacionRadio(),
        _emisoraActual = emisoraActual ?? (() => null),
-       _alError = alError {
+       _alError = alError,
+       _esPremium = esPremium ?? (() => true) {
     _suscripcion = this.servicio.estadoStream.listen((estado) {
       if (estado.tipo == EstadoGrabacionRadioTipo.error &&
           estado.error != null) {
@@ -65,6 +77,8 @@ class EstadoGrabacion extends ChangeNotifier {
   /// User-visible error sink (EstadoRadio routes it to its snackbar stream).
   final void Function(String mensaje)? _alError;
 
+  final bool Function() _esPremium;
+
   StreamSubscription<EstadoGrabacionRadio>? _suscripcion;
   AppLocalizations? _l10n;
 
@@ -87,7 +101,14 @@ class EstadoGrabacion extends ChangeNotifier {
   int get maxBytes => servicio.maxBytes;
   File? get ultimoArchivo => servicio.ultimoArchivo;
 
-  Future<void> iniciar({Duration? duracion}) async {
+  Future<ResultadoIniciarGrabacion> iniciar({Duration? duracion}) async {
+    // Freemium gate (freemium-gating spec "Free user starts a new
+    // recording"): the AUTHORITATIVE check, before touching the service at
+    // all. Management of already-existing recordings is untouched — this
+    // method only governs STARTING a new one.
+    if (!_esPremium()) {
+      return ResultadoIniciarGrabacion.requierePremium;
+    }
     final actual = _emisoraActual();
     // `emisoraActual` is set by `_cambiarFuente` for EVERY source, local
     // tracks included -- a local file becomes an `Emisora` whose `url` is the
@@ -97,12 +118,14 @@ class EstadoGrabacion extends ChangeNotifier {
     // that, whatever was playing was always a real station.
     if (actual == null || !esEmisoraGrabable(actual)) {
       _alError?.call(_textos.recordingSelectStationFirst);
-      return;
+      return ResultadoIniciarGrabacion.error;
     }
     try {
       await servicio.iniciar(actual, duracion: duracion);
+      return ResultadoIniciarGrabacion.iniciada;
     } catch (e) {
       _alError?.call(_textos.recordingStartError(e.toString()));
+      return ResultadoIniciarGrabacion.error;
     }
   }
 

lib/estado/estado_radio.dart

@@ -47,6 +47,10 @@ class EstadoRadio extends ChangeNotifier {
     Future<File> Function()? resolverArchivoCustom,
     FuenteEmisorasAuto? fuenteAuto,
     bool iniciarAutomaticamente = true,
+    // iap-freemium-unlock (Design ADR-3): threaded straight through to the
+    // internal `EstadoGrabacion` below — `EstadoRadio` itself has no gated
+    // behavior of its own.
+    bool Function()? esPremium,
   }) : audio = audio ?? ServicioAudio(),
        favoritos = favoritos ?? ServicioFavoritos(),
        radio = radio ?? ServicioRadio(),
@@ -66,6 +70,7 @@ class EstadoRadio extends ChangeNotifier {
       servicio: servicioGrabacion ?? ServicioGrabacionRadio(prefs: prefs),
       emisoraActual: () => emisoraActual,
       alError: _errorController.add,
+      esPremium: esPremium,
     );
     busqueda = EstadoBusqueda(
       radio: this.radio,

lib/l10n/app_ar.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "إصلاح",
   "alarmDiagnosticsIntentUnavailable": "تعذّر فتح شاشة الإعدادات هذه على هذا الهاتف. حاول البحث عنها يدويًا في الإعدادات.",
   "alarmDiagnosticsUnavailableHint": "لم نتمكّن بعد من التحقق من إعدادات المنبه الخاصة بك.",
-  "autoEqDisableOption": "تعطيل"
+  "autoEqDisableOption": "تعطيل",
+  "funcionPremium": "ميزة مميزة",
+  "limiteAlarmasAlcanzado": "لقد وصلت إلى الحد المجاني وهو 5 منبهات.",
+  "desbloquearPremium": "فتح النسخة المميزة",
+  "restaurarCompras": "استعادة المشتريات"
 }

lib/l10n/app_bn.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "সমাধান করুন",
   "alarmDiagnosticsIntentUnavailable": "এই ফোনে সেই সেটিংস স্ক্রিনটি খোলা যায়নি। সেটিংসে ম্যানুয়ালি খুঁজে দেখার চেষ্টা করুন।",
   "alarmDiagnosticsUnavailableHint": "আমরা এখনও আপনার অ্যালার্ম সেটিংস পরীক্ষা করতে পারিনি।",
-  "autoEqDisableOption": "বন্ধ করুন"
+  "autoEqDisableOption": "বন্ধ করুন",
+  "funcionPremium": "প্রিমিয়াম বৈশিষ্ট্য",
+  "limiteAlarmasAlcanzado": "আপনি বিনামূল্যে ৫টি অ্যালার্মের সীমায় পৌঁছেছেন।",
+  "desbloquearPremium": "প্রিমিয়াম আনলক করুন",
+  "restaurarCompras": "কেনাকাটা পুনরুদ্ধার করুন"
 }

lib/l10n/app_de.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "Beheben",
   "alarmDiagnosticsIntentUnavailable": "Diese Einstellungsseite konnte auf diesem Telefon nicht geöffnet werden. Suche sie manuell in den Einstellungen.",
   "alarmDiagnosticsUnavailableHint": "Wir konnten deine Alarmeinstellungen noch nicht prüfen.",
-  "autoEqDisableOption": "Deaktivieren"
+  "autoEqDisableOption": "Deaktivieren",
+  "funcionPremium": "Premium-Funktion",
+  "limiteAlarmasAlcanzado": "Du hast das kostenlose Limit von 5 Weckern erreicht.",
+  "desbloquearPremium": "Premium freischalten",
+  "restaurarCompras": "Käufe wiederherstellen"
 }

lib/l10n/app_en.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "Fix this",
   "alarmDiagnosticsIntentUnavailable": "Couldn't open that settings screen on this phone. Try looking for it manually in Settings.",
   "alarmDiagnosticsUnavailableHint": "We couldn't check your alarm settings yet.",
-  "autoEqDisableOption": "Disable"
+  "autoEqDisableOption": "Disable",
+  "funcionPremium": "Premium Feature",
+  "limiteAlarmasAlcanzado": "You've reached the free 5-alarm limit.",
+  "desbloquearPremium": "Unlock Premium",
+  "restaurarCompras": "Restore purchases"
 }

lib/l10n/app_es.arb

@@ -856,5 +856,9 @@
   "alarmDiagnosticsFixAction": "Solucionar",
   "alarmDiagnosticsIntentUnavailable": "No se pudo abrir esa pantalla de ajustes en este teléfono. Buscala manualmente en Ajustes.",
   "alarmDiagnosticsUnavailableHint": "Todavía no pudimos revisar tus ajustes de alarma.",
-  "autoEqDisableOption": "Desactivar"
+  "autoEqDisableOption": "Desactivar",
+  "funcionPremium": "Función Premium",
+  "limiteAlarmasAlcanzado": "Has alcanzado el límite de 5 alarmas gratuitas.",
+  "desbloquearPremium": "Desbloquear Premium",
+  "restaurarCompras": "Restaurar compras"
 }

lib/l10n/app_fr.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "Corriger",
   "alarmDiagnosticsIntentUnavailable": "Impossible d'ouvrir cet écran de paramètres sur ce téléphone. Essayez de le trouver manuellement dans les Paramètres.",
   "alarmDiagnosticsUnavailableHint": "Nous n'avons pas encore pu vérifier vos paramètres d'alarme.",
-  "autoEqDisableOption": "Désactiver"
+  "autoEqDisableOption": "Désactiver",
+  "funcionPremium": "Fonctionnalité Premium",
+  "limiteAlarmasAlcanzado": "Vous avez atteint la limite gratuite de 5 alarmes.",
+  "desbloquearPremium": "Débloquer Premium",
+  "restaurarCompras": "Restaurer les achats"
 }

lib/l10n/app_hi.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "ठीक करें",
   "alarmDiagnosticsIntentUnavailable": "इस फ़ोन पर वह सेटिंग्स स्क्रीन नहीं खोली जा सकी। कृपया सेटिंग्स में इसे खुद ढूंढने की कोशिश करें।",
   "alarmDiagnosticsUnavailableHint": "हम अभी तक आपकी अलार्म सेटिंग्स जांच नहीं पाए हैं।",
-  "autoEqDisableOption": "बंद करें"
+  "autoEqDisableOption": "बंद करें",
+  "funcionPremium": "प्रीमियम सुविधा",
+  "limiteAlarmasAlcanzado": "आप मुफ़्त 5 अलार्म की सीमा तक पहुँच गए हैं।",
+  "desbloquearPremium": "प्रीमियम अनलॉक करें",
+  "restaurarCompras": "खरीदारी पुनर्स्थापित करें"
 }

lib/l10n/app_id.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "Perbaiki",
   "alarmDiagnosticsIntentUnavailable": "Tidak bisa membuka layar pengaturan itu di ponsel ini. Coba cari secara manual di Pengaturan.",
   "alarmDiagnosticsUnavailableHint": "Kami belum bisa memeriksa pengaturan alarmmu.",
-  "autoEqDisableOption": "Nonaktifkan"
+  "autoEqDisableOption": "Nonaktifkan",
+  "funcionPremium": "Fitur Premium",
+  "limiteAlarmasAlcanzado": "Anda telah mencapai batas gratis 5 alarm.",
+  "desbloquearPremium": "Buka Premium",
+  "restaurarCompras": "Pulihkan pembelian"
 }

lib/l10n/app_it.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "Risolvi",
   "alarmDiagnosticsIntentUnavailable": "Non è stato possibile aprire questa schermata delle impostazioni su questo telefono. Prova a cercarla manualmente nelle Impostazioni.",
   "alarmDiagnosticsUnavailableHint": "Non abbiamo ancora potuto controllare le impostazioni della sveglia.",
-  "autoEqDisableOption": "Disattiva"
+  "autoEqDisableOption": "Disattiva",
+  "funcionPremium": "Funzione Premium",
+  "limiteAlarmasAlcanzado": "Hai raggiunto il limite gratuito di 5 sveglie.",
+  "desbloquearPremium": "Sblocca Premium",
+  "restaurarCompras": "Ripristina acquisti"
 }

lib/l10n/app_ja.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "修正する",
   "alarmDiagnosticsIntentUnavailable": "この端末では設定画面を開けませんでした。設定アプリ内で手動で探してみてください。",
   "alarmDiagnosticsUnavailableHint": "アラームの設定をまだ確認できていません。",
-  "autoEqDisableOption": "無効化"
+  "autoEqDisableOption": "無効化",
+  "funcionPremium": "プレミアム機能",
+  "limiteAlarmasAlcanzado": "無料プランのアラーム上限（5件）に達しました。",
+  "desbloquearPremium": "プレミアムを解除",
+  "restaurarCompras": "購入を復元"
 }

lib/l10n/app_pt.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "Resolver",
   "alarmDiagnosticsIntentUnavailable": "Não foi possível abrir essa tela de configurações neste telefone. Tente procurá-la manualmente nas Configurações.",
   "alarmDiagnosticsUnavailableHint": "Ainda não conseguimos verificar as configurações do seu alarme.",
-  "autoEqDisableOption": "Desativar"
+  "autoEqDisableOption": "Desativar",
+  "funcionPremium": "Recurso Premium",
+  "limiteAlarmasAlcanzado": "Você atingiu o limite gratuito de 5 alarmes.",
+  "desbloquearPremium": "Desbloquear Premium",
+  "restaurarCompras": "Restaurar compras"
 }

lib/l10n/app_ru.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "Исправить",
   "alarmDiagnosticsIntentUnavailable": "Не удалось открыть этот экран настроек на этом телефоне. Попробуйте найти его вручную в Настройках.",
   "alarmDiagnosticsUnavailableHint": "Мы пока не смогли проверить настройки вашего будильника.",
-  "autoEqDisableOption": "Отключить"
+  "autoEqDisableOption": "Отключить",
+  "funcionPremium": "Премиум-функция",
+  "limiteAlarmasAlcanzado": "Вы достигли бесплатного лимита в 5 будильников.",
+  "desbloquearPremium": "Разблокировать Премиум",
+  "restaurarCompras": "Восстановить покупки"
 }

lib/l10n/app_zh.arb

@@ -897,5 +897,9 @@
   "alarmDiagnosticsFixAction": "解决",
   "alarmDiagnosticsIntentUnavailable": "无法在此手机上打开该设置界面。请尝试在设置中手动查找。",
   "alarmDiagnosticsUnavailableHint": "我们还无法检查你的闹钟设置。",
-  "autoEqDisableOption": "关闭"
+  "autoEqDisableOption": "关闭",
+  "funcionPremium": "高级功能",
+  "limiteAlarmasAlcanzado": "您已达到免费版 5 个闹钟的上限。",
+  "desbloquearPremium": "解锁高级版",
+  "restaurarCompras": "恢复购买"
 }

lib/l10n/gen/app_localizations.dart

@@ -3325,6 +3325,30 @@ abstract class AppLocalizations {
   /// In es, this message translates to:
   /// **'Desactivar'**
   String get autoEqDisableOption;
+
+  /// No description provided for @funcionPremium.
+  ///
+  /// In es, this message translates to:
+  /// **'Función Premium'**
+  String get funcionPremium;
+
+  /// No description provided for @limiteAlarmasAlcanzado.
+  ///
+  /// In es, this message translates to:
+  /// **'Has alcanzado el límite de 5 alarmas gratuitas.'**
+  String get limiteAlarmasAlcanzado;
+
+  /// No description provided for @desbloquearPremium.
+  ///
+  /// In es, this message translates to:
+  /// **'Desbloquear Premium'**
+  String get desbloquearPremium;
+
+  /// No description provided for @restaurarCompras.
+  ///
+  /// In es, this message translates to:
+  /// **'Restaurar compras'**
+  String get restaurarCompras;
 }
 
 class _AppLocalizationsDelegate

lib/l10n/gen/app_localizations_ar.dart

@@ -1840,4 +1840,17 @@ class AppLocalizationsAr extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'تعطيل';
+
+  @override
+  String get funcionPremium => 'ميزة مميزة';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'لقد وصلت إلى الحد المجاني وهو 5 منبهات.';
+
+  @override
+  String get desbloquearPremium => 'فتح النسخة المميزة';
+
+  @override
+  String get restaurarCompras => 'استعادة المشتريات';
 }

lib/l10n/gen/app_localizations_bn.dart

@@ -1851,4 +1851,17 @@ class AppLocalizationsBn extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'বন্ধ করুন';
+
+  @override
+  String get funcionPremium => 'প্রিমিয়াম বৈশিষ্ট্য';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'আপনি বিনামূল্যে ৫টি অ্যালার্মের সীমায় পৌঁছেছেন।';
+
+  @override
+  String get desbloquearPremium => 'প্রিমিয়াম আনলক করুন';
+
+  @override
+  String get restaurarCompras => 'কেনাকাটা পুনরুদ্ধার করুন';
 }

lib/l10n/gen/app_localizations_de.dart

@@ -1864,4 +1864,17 @@ class AppLocalizationsDe extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Deaktivieren';
+
+  @override
+  String get funcionPremium => 'Premium-Funktion';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'Du hast das kostenlose Limit von 5 Weckern erreicht.';
+
+  @override
+  String get desbloquearPremium => 'Premium freischalten';
+
+  @override
+  String get restaurarCompras => 'Käufe wiederherstellen';
 }

lib/l10n/gen/app_localizations_en.dart

@@ -1843,4 +1843,17 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Disable';
+
+  @override
+  String get funcionPremium => 'Premium Feature';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'You\'ve reached the free 5-alarm limit.';
+
+  @override
+  String get desbloquearPremium => 'Unlock Premium';
+
+  @override
+  String get restaurarCompras => 'Restore purchases';
 }

lib/l10n/gen/app_localizations_es.dart

@@ -1857,4 +1857,17 @@ class AppLocalizationsEs extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Desactivar';
+
+  @override
+  String get funcionPremium => 'Función Premium';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'Has alcanzado el límite de 5 alarmas gratuitas.';
+
+  @override
+  String get desbloquearPremium => 'Desbloquear Premium';
+
+  @override
+  String get restaurarCompras => 'Restaurar compras';
 }

lib/l10n/gen/app_localizations_fr.dart

@@ -1870,4 +1870,17 @@ class AppLocalizationsFr extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Désactiver';
+
+  @override
+  String get funcionPremium => 'Fonctionnalité Premium';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'Vous avez atteint la limite gratuite de 5 alarmes.';
+
+  @override
+  String get desbloquearPremium => 'Débloquer Premium';
+
+  @override
+  String get restaurarCompras => 'Restaurer les achats';
 }

lib/l10n/gen/app_localizations_hi.dart

@@ -1844,4 +1844,17 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'बंद करें';
+
+  @override
+  String get funcionPremium => 'प्रीमियम सुविधा';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'आप मुफ़्त 5 अलार्म की सीमा तक पहुँच गए हैं।';
+
+  @override
+  String get desbloquearPremium => 'प्रीमियम अनलॉक करें';
+
+  @override
+  String get restaurarCompras => 'खरीदारी पुनर्स्थापित करें';
 }

lib/l10n/gen/app_localizations_id.dart

@@ -1854,4 +1854,17 @@ class AppLocalizationsId extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Nonaktifkan';
+
+  @override
+  String get funcionPremium => 'Fitur Premium';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'Anda telah mencapai batas gratis 5 alarm.';
+
+  @override
+  String get desbloquearPremium => 'Buka Premium';
+
+  @override
+  String get restaurarCompras => 'Pulihkan pembelian';
 }

lib/l10n/gen/app_localizations_it.dart

@@ -1867,4 +1867,17 @@ class AppLocalizationsIt extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Disattiva';
+
+  @override
+  String get funcionPremium => 'Funzione Premium';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'Hai raggiunto il limite gratuito di 5 sveglie.';
+
+  @override
+  String get desbloquearPremium => 'Sblocca Premium';
+
+  @override
+  String get restaurarCompras => 'Ripristina acquisti';
 }

lib/l10n/gen/app_localizations_ja.dart

@@ -1791,4 +1791,16 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => '無効化';
+
+  @override
+  String get funcionPremium => 'プレミアム機能';
+
+  @override
+  String get limiteAlarmasAlcanzado => '無料プランのアラーム上限（5件）に達しました。';
+
+  @override
+  String get desbloquearPremium => 'プレミアムを解除';
+
+  @override
+  String get restaurarCompras => '購入を復元';
 }

lib/l10n/gen/app_localizations_pt.dart

@@ -1854,4 +1854,17 @@ class AppLocalizationsPt extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Desativar';
+
+  @override
+  String get funcionPremium => 'Recurso Premium';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'Você atingiu o limite gratuito de 5 alarmes.';
+
+  @override
+  String get desbloquearPremium => 'Desbloquear Premium';
+
+  @override
+  String get restaurarCompras => 'Restaurar compras';
 }

lib/l10n/gen/app_localizations_ru.dart

@@ -1861,4 +1861,17 @@ class AppLocalizationsRu extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => 'Отключить';
+
+  @override
+  String get funcionPremium => 'Премиум-функция';
+
+  @override
+  String get limiteAlarmasAlcanzado =>
+      'Вы достигли бесплатного лимита в 5 будильников.';
+
+  @override
+  String get desbloquearPremium => 'Разблокировать Премиум';
+
+  @override
+  String get restaurarCompras => 'Восстановить покупки';
 }

lib/l10n/gen/app_localizations_zh.dart

@@ -1776,4 +1776,16 @@ class AppLocalizationsZh extends AppLocalizations {
 
   @override
   String get autoEqDisableOption => '关闭';
+
+  @override
+  String get funcionPremium => '高级功能';
+
+  @override
+  String get limiteAlarmasAlcanzado => '您已达到免费版 5 个闹钟的上限。';
+
+  @override
+  String get desbloquearPremium => '解锁高级版';
+
+  @override
+  String get restaurarCompras => '恢复购买';
 }

lib/main.dart

@@ -5,6 +5,7 @@ import 'dart:ui' as ui;
 import 'package:audio_service/audio_service.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:google_mobile_ads/google_mobile_ads.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'app.dart';
 import 'servicios/arranque_audio.dart';
@@ -12,6 +13,7 @@ import 'servicios/musica_local_auto.dart';
 import 'servicios/navegacion_auto.dart';
 import 'servicios/servicio_audio.dart';
 import 'servicios/servicio_audio_session.dart';
+import 'servicios/servicio_compras.dart';
 import 'servicios/servicio_presets_personalizados.dart';
 import 'tema/pluriwave_tokens.dart';
 
@@ -104,6 +106,13 @@ Future<void> main() async {
   // actually take effect anyway.
   unawaited(aplicarPoliticaOrientacion());
 
+  // iap-freemium-unlock: neither SDK init call blocks `runApp` — a purchase
+  // stream subscription and an ad-SDK warm-up are both safe to finish late
+  // (mirrors `aplicarPoliticaOrientacion`'s "cosmetic, never gates startup"
+  // rule immediately above).
+  unawaited(MobileAds.instance.initialize());
+  final compras = ServicioComprasPlayBilling();
+
   // S3-R4: single SharedPreferences instance resolved once at startup and
   // injected into every state/service below.
   final prefs = await SharedPreferences.getInstance();
@@ -155,7 +164,7 @@ Future<void> main() async {
   }
 
   Widget construirApp() => _OrientacionResponsiveApp(
-    child: PluriWaveApp(prefs: prefs, fuenteAuto: fuenteAuto),
+    child: PluriWaveApp(prefs: prefs, fuenteAuto: fuenteAuto, compras: compras),
   );
 
   final resultado = await esperarArranqueAudio(handlerFuturo);

lib/pantallas/ajustes/pantalla_ajustes_emisoras_personalizadas.dart

@@ -6,6 +6,7 @@ import '../../estado/estado_radio.dart';
 import '../../l10n/display_names.dart';
 import '../../l10n/gen/app_localizations.dart';
 import '../../modelos/emisora.dart';
+import '../../servicios/servicio_anuncios.dart';
 import '../../widgets/pluri_glass_surface.dart';
 import '../../widgets/pluri_layout.dart';
 import '../../widgets/pluri_push_scaffold.dart';
@@ -105,6 +106,11 @@ class _CuerpoEmisorasPersonalizadas extends StatelessWidget {
   }
 
   Future<void> _mostrarFormularioAnadir(BuildContext context) async {
+    // ad-display spec "Interstitial Before Manual Station Add" (design.md
+    // ADR-6): fires on the CTA tap, before the form even opens — a no-op
+    // for premium (ServicioAnuncios' own entitlement gate).
+    await context.read<ServicioAnuncios>().intentarInterstitial();
+    if (!context.mounted) return;
     await showModalBottomSheet(
       context: context,
       isScrollControlled: true,

lib/pantallas/pantalla_ajustes.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
 import '../estado/estado_ecualizador.dart';
+import '../estado/estado_entitlement.dart';
 import '../estado/estado_grabacion.dart';
 import '../estado/estado_idioma.dart';
 import '../estado/estado_radio.dart';
@@ -10,6 +11,7 @@ import '../l10n/gen/app_localizations.dart';
 import '../modelos/archivo_grabacion.dart';
 import '../modelos/emisora.dart';
 import '../tema/pluriwave_tokens.dart';
+import '../widgets/hoja_premium.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_push_scaffold.dart';
 import '../widgets/pluri_root_header.dart';
@@ -99,6 +101,9 @@ class _AjustesContent extends StatelessWidget {
     final idioma = context.select<EstadoIdioma, Locale?>(
       (e) => e.localeSeleccionado,
     );
+    final esPremium = context.select<EstadoEntitlement, bool>(
+      (e) => e.esPremium,
+    );
 
     return Column(
       children: [
@@ -256,6 +261,18 @@ class _AjustesContent extends StatelessWidget {
         GrupoAjustes(
           titulo: l10n.settingsGroupApplicationTitle,
           filas: [
+            // freemium-gating spec "Settings always shows a premium row":
+            // a persistent buy row (free tier) or a premium-active state
+            // with restore access (premium tier) — both open the same
+            // paywall sheet, which adapts its own body to the tier.
+            FilaAjuste(
+              key: const ValueKey('ajustes-fila-premium'),
+              icon: Icons.workspace_premium_rounded,
+              iconColor: PluriWaveTokens.brand,
+              titulo: l10n.funcionPremium,
+              valor: esPremium ? l10n.equalizerActive : null,
+              onTap: () => mostrarHojaPremium(context),
+            ),
             FilaAjuste(
               icon: Icons.language_rounded,
               titulo: l10n.languageSectionTitle,

lib/pantallas/pantalla_alarmas.dart

@@ -9,10 +9,12 @@ import '../l10n/app_localizations_ext.dart';
 import '../l10n/gen/app_localizations.dart';
 import '../modelos/alarma_musical.dart';
 import '../modelos/emisora.dart';
+import '../servicios/servicio_anuncios.dart';
 import '../servicios/servicio_programacion_alarmas.dart';
 import '../tema/pluriwave_theme.dart';
 import '../tema/pluriwave_tokens.dart';
 import '../widgets/editor_hora_inline.dart';
+import '../widgets/hoja_premium.dart';
 import '../widgets/pluri_glass_surface.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_push_scaffold.dart';
@@ -105,6 +107,21 @@ class PantallaAlarmas extends StatelessWidget {
     BuildContext context, {
     AlarmaMusical? alarma,
   }) async {
+    // ADR-6 ordering (design.md): for a genuinely NEW alarm (no [alarma]),
+    // the cap-check + maybe-interstitial happen HERE, before the editor
+    // ever opens — "puedeCrearAlarma -> if false, show the limit message
+    // and no ad; if true, maybe-interstitial, then open the editor".
+    // Editing an existing alarm skips both checks entirely: it is never
+    // capped and never triggers the interstitial.
+    if (alarma == null) {
+      final estado = context.read<EstadoAlarmas>();
+      if (!estado.puedeCrearAlarma()) {
+        _mostrarLimiteAlarmas(context);
+        return;
+      }
+      await context.read<ServicioAnuncios>().intentarInterstitial();
+      if (!context.mounted) return;
+    }
     await showModalBottomSheet<void>(
       context: context,
       isScrollControlled: true,
@@ -113,6 +130,22 @@ class PantallaAlarmas extends StatelessWidget {
       builder: (_) => _EditorAlarmaSheet(alarma: alarma),
     );
   }
+
+  /// Freemium-gating spec "Alarm Cap UX Never Bare-Jumps To Paywall": an
+  /// explanatory message with a SECONDARY unlock action — never a direct
+  /// paywall navigation as the sole response to hitting the cap.
+  void _mostrarLimiteAlarmas(BuildContext context) {
+    final l10n = AppLocalizations.of(context);
+    ScaffoldMessenger.of(context).showSnackBar(
+      SnackBar(
+        content: Text(l10n.limiteAlarmasAlcanzado),
+        action: SnackBarAction(
+          label: l10n.desbloquearPremium,
+          onPressed: () => mostrarHojaPremium(context),
+        ),
+      ),
+    );
+  }
 }
 
 class _PanelProximaAlarma extends StatelessWidget {
@@ -1186,8 +1219,34 @@ class _EditorAlarmaSheetState extends State<_EditorAlarmaSheet> {
           sonidoInterno: _sonidoInterno,
           activa: true,
         );
-    await estado.guardarAlarma(alarma);
-    if (mounted) Navigator.pop(context);
+    // The cap-check + interstitial already ran in `PantallaAlarmas
+    // ._abrirEditor` BEFORE this sheet ever opened (ADR-6 ordering: "then
+    // open the editor"). This is only the defense-in-depth backstop against
+    // the state-layer choke point — e.g. a 2nd device created alarms while
+    // this sheet was open — the true authority is `guardarAlarma` itself.
+    final resultado = await estado.guardarAlarma(alarma);
+    if (!mounted) return;
+    if (resultado == ResultadoGuardarAlarma.limiteAlcanzado) {
+      _mostrarLimiteAlarmas(context);
+      return;
+    }
+    Navigator.pop(context);
+  }
+
+  /// Freemium-gating spec "Alarm Cap UX Never Bare-Jumps To Paywall": an
+  /// explanatory message with a SECONDARY unlock action — never a direct
+  /// paywall navigation as the sole response to hitting the cap.
+  void _mostrarLimiteAlarmas(BuildContext context) {
+    final l10n = AppLocalizations.of(context);
+    ScaffoldMessenger.of(context).showSnackBar(
+      SnackBar(
+        content: Text(l10n.limiteAlarmasAlcanzado),
+        action: SnackBarAction(
+          label: l10n.desbloquearPremium,
+          onPressed: () => mostrarHojaPremium(context),
+        ),
+      ),
+    );
   }
 
   List<Emisora> _favoritasConSeleccion(List<Emisora> favoritas) {

lib/pantallas/pantalla_favoritos.dart

@@ -6,6 +6,7 @@ import '../l10n/display_names.dart';
 import '../l10n/gen/app_localizations.dart';
 import '../modelos/emisora.dart';
 import '../modelos/grupo_favoritos.dart';
+import '../servicios/servicio_anuncios.dart';
 import '../tema/pluriwave_tokens.dart';
 import '../widgets/fila_emisora_plana.dart';
 import '../widgets/pluri_icon.dart';
@@ -38,6 +39,11 @@ class _PantallaFavoritosState extends State<PantallaFavoritos> {
   String? _grupoSeleccionadoId;
 
   Future<void> _abrirFormularioEmisoraPersonalizada() async {
+    // ad-display spec "Interstitial Before Manual Station Add" (design.md
+    // ADR-6): fires on the CTA tap, before the form even opens — a no-op
+    // for premium (ServicioAnuncios' own entitlement gate).
+    await context.read<ServicioAnuncios>().intentarInterstitial();
+    if (!mounted) return;
     await showModalBottomSheet(
       context: context,
       isScrollControlled: true,

lib/pantallas/pantalla_reproductor.dart

@@ -17,6 +17,7 @@ import '../tema/pluri_animate.dart';
 import '../tema/pluriwave_theme.dart';
 import '../tema/pluriwave_tokens.dart';
 import '../widgets/ecualizador_widget.dart';
+import '../widgets/hoja_premium.dart';
 import '../widgets/pluri_glass_surface.dart';
 import '../widgets/pluri_premium_widgets.dart';
 import '../widgets/pluri_push_scaffold.dart';
@@ -597,6 +598,28 @@ class _GrabacionWidget extends StatelessWidget {
     }
   }
 
+  /// Freemium gate choke point at the UI layer (freemium-gating spec "Free
+  /// user starts a new recording"): all 3 record-start call sites route
+  /// through here. [ctx] is the picker sheet/dialog's own (short-lived)
+  /// context — closed FIRST (matching the pre-existing pop-then-done shape).
+  /// [contextExterno] is the screen's own longer-lived context, used ONLY to
+  /// react to the AUTHORITATIVE [EstadoGrabacion.iniciar] result: a
+  /// free-tier block opens the paywall there instead of a plain error, since
+  /// [ctx] is already gone by then.
+  Future<void> _iniciarGrabacionYCerrar(
+    BuildContext ctx,
+    BuildContext contextExterno,
+    EstadoGrabacion grabacion, {
+    Duration? duracion,
+  }) async {
+    final resultado = await grabacion.iniciar(duracion: duracion);
+    if (ctx.mounted) Navigator.pop(ctx);
+    if (resultado == ResultadoIniciarGrabacion.requierePremium &&
+        contextExterno.mounted) {
+      await mostrarHojaPremium(contextExterno);
+    }
+  }
+
   void _mostrarDialogoGrabacion(BuildContext context) {
     final grabacion = context.read<EstadoGrabacion>();
     showModalBottomSheet(
@@ -626,10 +649,12 @@ class _GrabacionWidget extends StatelessWidget {
                           size: 18,
                         ),
                         label: Text(AppLocalizations.of(ctx).indefiniteOption),
-                        onPressed: () {
-                          grabacion.iniciar();
-                          Navigator.pop(ctx);
-                        },
+                        onPressed:
+                            () => _iniciarGrabacionYCerrar(
+                              ctx,
+                              context,
+                              grabacion,
+                            ),
                       ),
                       for (final opcion in _opciones)
                         ActionChip(
@@ -642,10 +667,13 @@ class _GrabacionWidget extends StatelessWidget {
                                   opcion.duracion.inSeconds,
                                 ),
                           ),
-                          onPressed: () {
-                            grabacion.iniciar(duracion: opcion.duracion);
-                            Navigator.pop(ctx);
-                          },
+                          onPressed:
+                              () => _iniciarGrabacionYCerrar(
+                                ctx,
+                                context,
+                                grabacion,
+                                duracion: opcion.duracion,
+                              ),
                         ),
                       ActionChip(
                         avatar: const Icon(Icons.tune_rounded, size: 18),
@@ -718,8 +746,12 @@ class _GrabacionWidget extends StatelessWidget {
                     seconds: segundos,
                   );
                   if (duracion <= Duration.zero) return;
-                  grabacion.iniciar(duracion: duracion);
-                  Navigator.pop(ctx);
+                  _iniciarGrabacionYCerrar(
+                    ctx,
+                    context,
+                    grabacion,
+                    duracion: duracion,
+                  );
                 },
                 child: Text(AppLocalizations.of(ctx).recordAction),
               ),

lib/pantallas/pantalla_vacaciones.dart

@@ -8,6 +8,7 @@ import '../l10n/gen/app_localizations.dart';
 import '../modelos/alarma_musical.dart';
 import '../tema/pluriwave_theme.dart';
 import '../tema/pluriwave_tokens.dart';
+import '../widgets/hoja_premium.dart';
 import '../widgets/pluri_glass_surface.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_push_scaffold.dart';
@@ -927,7 +928,14 @@ class _EditorVacacionesSheetState extends State<_EditorVacacionesSheet> {
         fin: _fin,
         nombre: nombre,
       );
-      await estado.crearRangoVacaciones(rango);
+      // freemium-gating spec "Gated Feature Set": vacation creation is
+      // fully gated (unlike the alarm cap, there is no free allowance) —
+      // `crearRangoVacaciones` is the authoritative choke point.
+      final creada = await estado.crearRangoVacaciones(rango);
+      if (!creada) {
+        if (mounted) await mostrarHojaPremium(context);
+        return;
+      }
     }
     if (mounted) Navigator.pop(context);
   }

lib/servicios/navegacion_auto.dart

@@ -333,13 +333,43 @@ class ConstructorArbolAuto {
   /// [incluirMusicaLocal] is `true` (Design "Local root hidden until a folder
   /// is configured") — the caller passes `fuente.hayCarpetaConfigurada()`,
   /// keeping this builder itself synchronous and side-effect free.
-  List<MediaItem> raiz({required bool incluirMusicaLocal}) => [
+  ///
+  /// [premium] (iap-freemium-unlock, Design ADR-4): the ROOT keeps the exact
+  /// same visible folder labels for every tier — "keeps the same visible
+  /// folder labels for free users" is the explicit design choice, so a free
+  /// driver still sees a real, familiar menu rather than a wall of "Función
+  /// Premium" rows. The lock itself is enforced one level DOWN, at the
+  /// `getChildren` choke point (see [itemPremiumBloqueado] and
+  /// [respuestaBloqueadaPorEntitlement] below) — tapping any of these
+  /// folders as a free user reveals the lock there, never here.
+  List<MediaItem> raiz({
+    required bool incluirMusicaLocal,
+    required bool premium,
+  }) => [
     _carpeta(idFavoritos, 'Favoritos'),
     _carpeta(idTodas, 'Todas las emisoras'),
     _carpeta(idMisEmisoras, 'Mis emisoras'),
     if (incluirMusicaLocal) _carpeta(idMusicaLocal, 'Música Local'),
   ];
 
+  /// Free-tier id prefix reserved id (iap-freemium-unlock, Design ADR-4):
+  /// the single non-playable item every non-root folder collapses to for a
+  /// free-tier user. Hardcoded Spanish label, matching every other car-tree
+  /// label in this file (never routed through `AppLocalizations` —
+  /// established convention, see [_tituloMasLocal]'s doc).
+  static const idPremiumInfo = 'premium:info';
+
+  /// The single locked item shown for ANY non-root folder when the browsing
+  /// user is free tier (Design ADR-4, android-auto-media spec "Free-Tier
+  /// Reduced Root Browse"). Non-playable — selecting it is a no-op, never a
+  /// crash (Spec "Free-tier user selects a locked item").
+  MediaItem itemPremiumBloqueado() => MediaItem(
+    id: idPremiumInfo,
+    title: 'Función Premium',
+    playable: false,
+    extras: _contentStyleLista,
+  );
+
   MediaItem _carpeta(String id, String titulo) => MediaItem(
     id: id,
     title: titulo,
@@ -899,6 +929,26 @@ class ConstructorArbolAuto {
   }
 }
 
+/// Pure Android Auto browse-gate decision (iap-freemium-unlock, Design
+/// ADR-4): the AUTHORITATIVE `getChildren` choke point, called BEFORE any
+/// other resolution. For the root itself this NEVER blocks (the root always
+/// resolves through [ConstructorArbolAuto.raiz] instead, which stays
+/// visible for every tier). For any non-root [parentMediaId] and a free-tier
+/// [premium], it returns the single locked item regardless of what the id
+/// actually is — a stale/deep-linked `emisora:<uuid>` or folder id from
+/// before a downgrade is blocked exactly the same way as a legitimate
+/// current folder id (android-auto-media spec "Free-Tier Browse Never
+/// Leaks Real Content (Authoritative Backstop)"). Returns `null` when the
+/// caller should proceed with its normal resolution (root, or premium).
+List<MediaItem>? respuestaBloqueadaPorEntitlement({
+  required String parentMediaId,
+  required bool premium,
+}) {
+  if (parentMediaId == AudioService.browsableRootId) return null;
+  if (premium) return null;
+  return [ConstructorArbolAuto().itemPremiumBloqueado()];
+}
+
 /// Routing seam between a car-tapped `emisora:<uuid>` media id and the
 /// existing internal playback path (Design "playback coherence" — reuse
 /// over duplication). Resolves the uuid via [fuente], builds the same

lib/servicios/servicio_anuncios.dart

@@ -0,0 +1,117 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart' show debugPrint;
+import 'package:google_mobile_ads/google_mobile_ads.dart';
+
+/// TODO(ads): official Google TEST ad unit ids — AdMob has not provisioned
+/// real ones yet (design.md Open Questions). Swap these for the real banner
+/// / interstitial unit ids once available; never ship the test ids to
+/// production.
+const bannerAdUnitIdPrueba = 'ca-app-pub-3940256099942544/6300978111';
+const interstitialAdUnitIdPrueba = 'ca-app-pub-3940256099942544/1033173712';
+
+/// Ads port + AdMob adapter (Design "Interfaces / Contracts", ADR-6): owns
+/// the entitlement gate for both surfaces, the interstitial's session
+/// frequency cap, and is the ONLY `google_mobile_ads` call site besides
+/// `banner_anuncio_superior.dart`'s `BannerAd` widget wrapper. The frequency
+/// cap and premium gating are pure/injectable (`ahora`,
+/// `mostrarInterstitialImpl`) so they are unit-testable with a fake clock
+/// and zero AdMob platform channels (Design Testing Strategy).
+class ServicioAnuncios {
+  ServicioAnuncios({
+    bool Function()? esPremium,
+    DateTime Function()? ahora,
+    Future<bool> Function()? mostrarInterstitialImpl,
+  }) : _esPremium = esPremium ?? (() => false),
+       _ahora = ahora ?? DateTime.now,
+       _mostrarInterstitialImpl =
+           mostrarInterstitialImpl ?? _mostrarInterstitialAdMob;
+
+  /// Session-scoped cap (ad-display spec "Interstitial Frequency Cap"): at
+  /// most 2 interstitials per process lifetime.
+  static const maxInterstitialsPorSesion = 2;
+
+  /// Minimum spacing between two interstitials (ad-display spec, same
+  /// requirement).
+  static const separacionMinima = Duration(minutes: 3);
+
+  final bool Function() _esPremium;
+  final DateTime Function() _ahora;
+  final Future<bool> Function() _mostrarInterstitialImpl;
+
+  int _mostrados = 0;
+  DateTime? _ultimoMostrado;
+
+  /// Ad-display spec "Persistent Top Banner": absent entirely for premium.
+  bool get debeMostrarBanner => !_esPremium();
+
+  bool _dentroDelCap() {
+    if (_esPremium()) return false;
+    if (_mostrados >= maxInterstitialsPorSesion) return false;
+    final ultimo = _ultimoMostrado;
+    if (ultimo != null && _ahora().difference(ultimo) < separacionMinima) {
+      return false;
+    }
+    return true;
+  }
+
+  /// Attempts to show an interstitial for one of the two allowed CTAs (add
+  /// station manually, add alarm). Callers are responsible for the ADR-6
+  /// ordering invariant themselves (cap-check-before-interstitial for
+  /// add-alarm, so a refusal is never preceded by an ad) — this method only
+  /// owns entitlement + frequency-cap gating, never the caller's own
+  /// business-rule ordering.
+  ///
+  /// Returns whether an interstitial actually rendered. A failed/aborted ad
+  /// load (network, no fill) does NOT consume the session cap — only a
+  /// genuinely SHOWN ad does (Spec intent: the cap limits driver-facing
+  /// interruptions, not load attempts).
+  Future<bool> intentarInterstitial() async {
+    if (!_dentroDelCap()) return false;
+    final mostrado = await _mostrarInterstitialImpl();
+    if (mostrado) {
+      _mostrados++;
+      _ultimoMostrado = _ahora();
+    }
+    return mostrado;
+  }
+
+  static Future<bool> _mostrarInterstitialAdMob() async {
+    try {
+      final cargaCompleter = Completer<InterstitialAd?>();
+      await InterstitialAd.load(
+        adUnitId: interstitialAdUnitIdPrueba,
+        request: const AdRequest(),
+        adLoadCallback: InterstitialAdLoadCallback(
+          onAdLoaded: (ad) {
+            if (!cargaCompleter.isCompleted) cargaCompleter.complete(ad);
+          },
+          onAdFailedToLoad: (error) {
+            debugPrint('[PluriWave][anuncios] interstitial load ERROR $error');
+            if (!cargaCompleter.isCompleted) cargaCompleter.complete(null);
+          },
+        ),
+      );
+      final cargado = await cargaCompleter.future;
+      if (cargado == null) return false;
+
+      final cierreCompleter = Completer<void>();
+      cargado.fullScreenContentCallback = FullScreenContentCallback(
+        onAdDismissedFullScreenContent: (ad) {
+          ad.dispose();
+          if (!cierreCompleter.isCompleted) cierreCompleter.complete();
+        },
+        onAdFailedToShowFullScreenContent: (ad, error) {
+          ad.dispose();
+          if (!cierreCompleter.isCompleted) cierreCompleter.complete();
+        },
+      );
+      await cargado.show();
+      await cierreCompleter.future;
+      return true;
+    } catch (e) {
+      debugPrint('[PluriWave][anuncios] interstitial ERROR $e');
+      return false;
+    }
+  }
+}

lib/servicios/servicio_audio.dart

@@ -4,7 +4,9 @@ import 'dart:ui' show Locale;
 import 'package:audio_service/audio_service.dart';
 import 'package:flutter/foundation.dart' show debugPrint, visibleForTesting;
 import 'package:just_audio/just_audio.dart';
+import 'package:rxdart/rxdart.dart';
 
+import '../estado/estado_entitlement.dart' show esPremiumPersistido;
 import '../l10n/display_names.dart';
 import '../l10n/gen/app_localizations.dart';
 import '../modelos/emisora.dart';
@@ -36,6 +38,17 @@ PluriWaveAudioHandler? _handlerGlobal;
 
 void registrarHandler(PluriWaveAudioHandler handler) {
   _handlerGlobal = handler;
+  // iap-freemium-unlock (design.md Open Questions, orchestrator-resolved):
+  // on the free -> premium transition, actively invalidate every root-level
+  // browse id a head unit may have cached while locked, rather than waiting
+  // for its own re-bind — see [registrarNotificacionDesbloqueoAuto]'s doc.
+  registrarNotificacionDesbloqueoAuto(() {
+    handler.notificarHijosCambiaron(AudioService.browsableRootId);
+    handler.notificarHijosCambiaron(ConstructorArbolAuto.idFavoritos);
+    handler.notificarHijosCambiaron(ConstructorArbolAuto.idTodas);
+    handler.notificarHijosCambiaron(ConstructorArbolAuto.idMisEmisoras);
+    handler.notificarHijosCambiaron(ConstructorArbolAuto.idMusicaLocal);
+  });
 }
 
 // ─────────────────────────────────────────────────────────────────────────────
@@ -140,6 +153,41 @@ void registrarLimpiezaArranque(Future<void> Function() limpieza) {
   _limpiezaArranqueGlobal = limpieza;
 }
 
+/// Free -> premium Android Auto cache-invalidation hook (design.md Open
+/// Questions, orchestrator-resolved): registered from [registrarHandler] so
+/// `estado_entitlement.dart` can trigger it WITHOUT ever touching
+/// `PluriWaveAudioHandler` directly (that type cannot be constructed in a
+/// unit test — see [PluriWaveAudioHandler]'s own doc). `null` until a
+/// handler registers (headless cold bind, or a widget-only test that never
+/// wires audio) — [notificarDesbloqueoAuto] tolerates that silently.
+void Function()? _alDesbloquearAutoGlobal;
+
+/// Registers the hook [notificarDesbloqueoAuto] invokes. Exposed at module
+/// level (like every other `registrar*` seam in this file) purely so tests
+/// can inject a fake hook and assert it fires, without instantiating a real
+/// [PluriWaveAudioHandler].
+void registrarNotificacionDesbloqueoAuto(void Function() alDesbloquear) {
+  _alDesbloquearAutoGlobal = alDesbloquear;
+}
+
+/// Fires the registered free -> premium Android Auto invalidation hook, if
+/// any. A no-op before a handler ever registers — never throws.
+void notificarDesbloqueoAuto() {
+  _alDesbloquearAutoGlobal?.call();
+}
+
+/// Pure Android Auto play-path gate decision (iap-freemium-unlock, Design
+/// ADR-4): whether a station-switch dispatch (`playFromMediaId`,
+/// `playFromSearch`, `skipToNext`, `skipToPrevious`) must no-op for
+/// [premium]. This is the mandatory BACKSTOP alongside
+/// `respuestaBloqueadaPorEntitlement` (`navegacion_auto.dart`) — gating
+/// `getChildren` alone would leave a stale/cached `emisora:<uuid>` tap free
+/// to bypass browsing entirely (android-auto-media spec "Free-Tier Browse
+/// Never Leaks Real Content"). Deliberately does NOT gate `play`/`pause`/
+/// `stop` — transport control of whatever is ALREADY loaded stays free
+/// (Spec "Current-Station Playback Unaffected By Free Tier").
+bool debeBloquearCambioDeEmisora({required bool premium}) => !premium;
+
 /// Builds the phone-initiated "play a station" `MediaItem` (item 3, Android
 /// Auto fallback artwork): reuses [artUriPara] (`navegacion_auto.dart`) so a
 /// station with no usable favicon gets the SAME on-brand rotating fallback
@@ -638,6 +686,32 @@ class PluriWaveAudioHandler extends BaseAudioHandler
   /// Reconnect-on-stall state machine (Design 7.2, S7-R2).
   final ControladorReconexion _reconexion = ControladorReconexion();
 
+  /// Per-`parentMediaId` "children changed" subjects (iap-freemium-unlock,
+  /// design.md Open Questions): `audio_service`'s OWN internal listener
+  /// (registered once `AudioService.init` completes) subscribes to
+  /// [subscribeToChildren] and forwards every new value to the platform's
+  /// `notifyChildrenChanged` — the plugin's top-level `notifyChildrenChanged`
+  /// helper is deprecated precisely in favor of this stream-based path. A
+  /// `BehaviorSubject` per id, created lazily on first subscription;
+  /// [notificarHijosCambiaron] pushes a fresh (empty, content-agnostic)
+  /// value to trigger the platform notification for that id.
+  final _childrenSubjects = <String, BehaviorSubject<Map<String, dynamic>>>{};
+
+  @override
+  ValueStream<Map<String, dynamic>> subscribeToChildren(String parentMediaId) =>
+      _childrenSubjects.putIfAbsent(
+        parentMediaId,
+        () => BehaviorSubject<Map<String, dynamic>>.seeded(<String, dynamic>{}),
+      );
+
+  /// Invalidates a head unit's cached browse listing for [parentMediaId]
+  /// (Design "Open Questions" — actively invalidate on the free -> premium
+  /// transition rather than waiting for the head unit's own re-bind). A
+  /// no-op if nothing ever subscribed to this id.
+  void notificarHijosCambiaron(String parentMediaId) {
+    _childrenSubjects[parentMediaId]?.add(<String, dynamic>{});
+  }
+
   /// True while the handler is inside the reconnect window. [ServicioAudio]
   /// maps it to [EstadoReproduccion.reconectando] so the UI shows a loading
   /// indicator instead of an error during retries (S7-R3).
@@ -1521,6 +1595,12 @@ class PluriWaveAudioHandler extends BaseAudioHandler
   /// and a button that is present but inert is worse than no button.
   @override
   Future<void> skipToNext() async {
+    // iap-freemium-unlock (Design ADR-4 backstop): station-to-station
+    // skipping is a browse/switch action, blocked for free tier regardless
+    // of queue state. Current-station play/pause/stop is untouched.
+    if (debeBloquearCambioDeEmisora(premium: await esPremiumPersistido())) {
+      return;
+    }
     final cola = _colaLocal;
     if (cola == null) {
       if (_reproduciendoRadio) await _saltarEmisora(haciaAtras: false);
@@ -1542,6 +1622,10 @@ class PluriWaveAudioHandler extends BaseAudioHandler
   /// [skipToNext].
   @override
   Future<void> skipToPrevious() async {
+    // iap-freemium-unlock (Design ADR-4 backstop): mirrors [skipToNext].
+    if (debeBloquearCambioDeEmisora(premium: await esPremiumPersistido())) {
+      return;
+    }
     final cola = _colaLocal;
     if (cola == null) {
       if (_reproduciendoRadio) await _saltarEmisora(haciaAtras: true);
@@ -1640,6 +1724,9 @@ class PluriWaveAudioHandler extends BaseAudioHandler
     await _androidAudioSessionIdSub?.cancel();
     await _player.dispose();
     await _androidAudioSessionIdController.close();
+    for (final subject in _childrenSubjects.values) {
+      await subject.close();
+    }
     // Handler teardown: release the bootstrap-owned `AudioService.asyncError`
     // subscription too, so it cannot outlive the handler it was instrumenting.
     // Never throws out of teardown — a failing cleanup hook must not prevent
@@ -1670,11 +1757,25 @@ class PluriWaveAudioHandler extends BaseAudioHandler
   ]) async {
     try {
       final constructor = ConstructorArbolAuto();
+      // iap-freemium-unlock (Design ADR-4): the AUTHORITATIVE entitlement
+      // gate, resolved ONCE per call and checked BEFORE any other
+      // resolution — the backstop against a stale/deep-linked non-root id
+      // (android-auto-media spec "Free-Tier Browse Never Leaks Real
+      // Content"). Never blocks the root itself (see that function's doc).
+      final premium = await esPremiumPersistido();
+      final bloqueada = respuestaBloqueadaPorEntitlement(
+        parentMediaId: parentMediaId,
+        premium: premium,
+      );
+      if (bloqueada != null) return bloqueada;
       final fuenteLocal = _fuenteMusicaLocalGlobal;
       if (parentMediaId == AudioService.browsableRootId) {
         final incluirMusicaLocal =
             fuenteLocal != null && await fuenteLocal.hayCarpetaConfigurada();
-        return constructor.raiz(incluirMusicaLocal: incluirMusicaLocal);
+        return constructor.raiz(
+          incluirMusicaLocal: incluirMusicaLocal,
+          premium: premium,
+        );
       }
       final musicaLocal = await hijosMusicaLocal(
         parentMediaId,
@@ -1756,6 +1857,12 @@ class PluriWaveAudioHandler extends BaseAudioHandler
     Map<String, dynamic>? extras,
   ]) async {
     try {
+      // iap-freemium-unlock (Design ADR-4 backstop): voice search resolves a
+      // station and switches to it — a browse/switch action, blocked for
+      // free tier just like `playFromMediaId`/`skipToNext-Previous`.
+      if (debeBloquearCambioDeEmisora(premium: await esPremiumPersistido())) {
+        return;
+      }
       final fuente = _fuenteNavegacionGlobal;
       if (fuente == null) return;
       final candidatas = <Emisora>[
@@ -1779,6 +1886,16 @@ class PluriWaveAudioHandler extends BaseAudioHandler
     Map<String, dynamic>? extras,
   ]) async {
     try {
+      // iap-freemium-unlock (Design ADR-4 backstop): the mandatory backstop
+      // against a head-unit's CACHED browse tree — `getChildren` alone
+      // cannot stop a stale `emisora:<uuid>`/`pista:`/`eq_preset:` tap from
+      // a tree fetched before a downgrade (or from another device). Checked
+      // BEFORE every branch below, including local tracks and the
+      // equalizer (android-auto-media spec "Free-Tier Browse Never Leaks
+      // Real Content (Authoritative Backstop)").
+      if (debeBloquearCambioDeEmisora(premium: await esPremiumPersistido())) {
+        return;
+      }
       // Local-track playback (Design "Local Track Playback Reuses Existing
       // Pipeline", Spec "User selects a local track"): FIRST branch,
       // unconditional `return` — a `pista:` id never falls through to the

lib/servicios/servicio_compras.dart

@@ -0,0 +1,174 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart' show debugPrint;
+import 'package:in_app_purchase/in_app_purchase.dart';
+
+/// Outcome kinds the purchase stream can report (Design ADR-2). Mirrors
+/// `in_app_purchase`'s [PurchaseStatus] but stays a PluriWave-owned type so
+/// [EstadoEntitlement] never imports the plugin package directly — the SAME
+/// port-boundary discipline `PuertoAlarmasAndroid` already applies.
+enum TipoEventoCompra {
+  /// A fresh purchase completed successfully.
+  comprada,
+
+  /// [PuertoCompras.restaurar] found a prior purchase.
+  restaurada,
+
+  /// The user cancelled the purchase flow before it completed.
+  cancelada,
+
+  /// The purchase/restore flow failed (network, billing error, etc).
+  error,
+
+  /// [PuertoCompras.restaurar] completed with nothing to restore — NOT an
+  /// error (Spec "Restore finds nothing").
+  noEncontrada,
+
+  /// A purchase is in-flight (billing dialog shown, awaiting the user).
+  pendiente,
+}
+
+/// A single purchase-stream event (Design ADR-2). [mensaje] is populated
+/// only for [TipoEventoCompra.error], for diagnostics/logging — never shown
+/// to the user verbatim.
+class EventoCompra {
+  const EventoCompra(this.tipo, {this.mensaje});
+
+  final TipoEventoCompra tipo;
+  final String? mensaje;
+}
+
+/// Purchase I/O abstraction (Design ADR-2): [EstadoEntitlement] depends on
+/// this port, never on `in_app_purchase` directly — matches
+/// `EstadoAlarmas(android: PuertoAlarmasAndroid)`'s injection shape, and
+/// keeps Strict TDD viable with zero plugin channels in unit tests.
+abstract class PuertoCompras {
+  /// Broadcasts every purchase-flow outcome (Design ADR-2) — [comprar] and
+  /// [restaurar] do not return the outcome directly because
+  /// `in_app_purchase`'s own API is stream-based (a purchase can complete
+  /// asynchronously well after the call that started it, e.g. after leaving
+  /// and returning to the app).
+  Stream<EventoCompra> get eventos;
+
+  /// Starts the one-time non-consumable purchase flow.
+  Future<void> comprar();
+
+  /// Re-queries Play Billing for a prior purchase on this account.
+  Future<void> restaurar();
+}
+
+/// The SOLE `in_app_purchase` call site (Design ADR-2) — every other file
+/// depends on [PuertoCompras] instead.
+class ServicioComprasPlayBilling implements PuertoCompras {
+  ServicioComprasPlayBilling({InAppPurchase? inAppPurchase})
+    : _iap = inAppPurchase ?? InAppPurchase.instance {
+    _sub = _iap.purchaseStream.listen(
+      _alRecibirCompras,
+      onError: (Object error) {
+        debugPrint('[PluriWave][compras] purchaseStream ERROR $error');
+        _eventos.add(
+          EventoCompra(TipoEventoCompra.error, mensaje: error.toString()),
+        );
+      },
+    );
+  }
+
+  /// The single non-consumable product id (Design "Interfaces / Contracts").
+  static const idProducto = 'pluriwave_premium';
+
+  final InAppPurchase _iap;
+  final _eventos = StreamController<EventoCompra>.broadcast();
+  StreamSubscription<List<PurchaseDetails>>? _sub;
+
+  @override
+  Stream<EventoCompra> get eventos => _eventos.stream;
+
+  @override
+  Future<void> comprar() async {
+    try {
+      final disponible = await _iap.isAvailable();
+      if (!disponible) {
+        _eventos.add(
+          const EventoCompra(
+            TipoEventoCompra.error,
+            mensaje: 'Play Billing no disponible',
+          ),
+        );
+        return;
+      }
+      final respuesta = await _iap.queryProductDetails({idProducto});
+      final detalle = respuesta.productDetails.firstOrNull;
+      if (detalle == null) {
+        _eventos.add(
+          const EventoCompra(
+            TipoEventoCompra.error,
+            mensaje: 'Producto no encontrado en Play Console',
+          ),
+        );
+        return;
+      }
+      final parametros = PurchaseParam(productDetails: detalle);
+      await _iap.buyNonConsumable(purchaseParam: parametros);
+    } catch (e) {
+      debugPrint('[PluriWave][compras] comprar ERROR $e');
+      _eventos.add(EventoCompra(TipoEventoCompra.error, mensaje: e.toString()));
+    }
+  }
+
+  @override
+  Future<void> restaurar() async {
+    try {
+      await _iap.restorePurchases();
+    } catch (e) {
+      debugPrint('[PluriWave][compras] restaurar ERROR $e');
+      _eventos.add(EventoCompra(TipoEventoCompra.error, mensaje: e.toString()));
+    }
+  }
+
+  void _alRecibirCompras(List<PurchaseDetails> compras) {
+    if (compras.isEmpty) {
+      // `restorePurchases()` with nothing to restore completes without ever
+      // pushing a PurchaseDetails (Spec "Restore finds nothing") — there is
+      // no per-call correlation in this stream, so this fires on ANY empty
+      // batch. In practice `queryPastPurchases`/`restorePurchases` on an
+      // account with nothing to restore is the only source of an empty
+      // batch this stream would ever emit.
+      return;
+    }
+    for (final compra in compras) {
+      _eventos.add(
+        eventoDesdeEstadoCompra(compra.status, mensaje: compra.error?.message),
+      );
+      if (compra.pendingCompletePurchase) {
+        unawaited(_iap.completePurchase(compra));
+      }
+    }
+  }
+
+  Future<void> dispose() async {
+    await _sub?.cancel();
+    await _eventos.close();
+  }
+}
+
+/// Pure mapping from `in_app_purchase`'s [PurchaseStatus] to the
+/// PluriWave-owned [EventoCompra] (Design ADR-2's port boundary): pulled out
+/// of [ServicioComprasPlayBilling] so it is unit-testable with zero plugin
+/// channels, mirroring how `servicio_audio.dart` extracts its pure mapping
+/// helpers (e.g. `mapearEstadoProceso`) out of the un-instantiable handler.
+EventoCompra eventoDesdeEstadoCompra(PurchaseStatus status, {String? mensaje}) {
+  return switch (status) {
+    PurchaseStatus.pending => const EventoCompra(TipoEventoCompra.pendiente),
+    PurchaseStatus.purchased => const EventoCompra(TipoEventoCompra.comprada),
+    PurchaseStatus.restored => const EventoCompra(TipoEventoCompra.restaurada),
+    PurchaseStatus.error => EventoCompra(
+      TipoEventoCompra.error,
+      mensaje: mensaje,
+    ),
+    PurchaseStatus.canceled => const EventoCompra(TipoEventoCompra.cancelada),
+  };
+}
+
+extension<T> on List<T> {
+  T? get firstOrNull => isEmpty ? null : first;
+}

lib/widgets/banner_anuncio_superior.dart

@@ -0,0 +1,85 @@
+import 'package:flutter/material.dart';
+import 'package:google_mobile_ads/google_mobile_ads.dart';
+import 'package:provider/provider.dart';
+
+import '../estado/estado_entitlement.dart';
+import '../servicios/servicio_anuncios.dart';
+
+/// Entitlement-aware top-banner slot (Design ADR-6, ad-display spec
+/// "Persistent Top Banner, Never Overlapping Content"). Collapses to
+/// `SizedBox.shrink()` — zero reserved space, zero layout impact — whenever
+/// the user is premium OR no ad has finished loading yet; only a
+/// successfully loaded [BannerAd] renders a sized box around an [AdWidget].
+/// Callers place this as a plain sibling in a `Column` ABOVE the existing
+/// body (`app.dart`'s `_PaginaPrincipalState.build`) — this widget itself
+/// never wraps its parent in a `Stack`/overlay.
+class BannerAnuncioSuperior extends StatefulWidget {
+  const BannerAnuncioSuperior({super.key});
+
+  @override
+  State<BannerAnuncioSuperior> createState() => _BannerAnuncioSuperiorState();
+}
+
+class _BannerAnuncioSuperiorState extends State<BannerAnuncioSuperior> {
+  BannerAd? _bannerAd;
+  bool _cargado = false;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final servicio = context.read<ServicioAnuncios>();
+    if (_bannerAd == null && servicio.debeMostrarBanner) {
+      _cargarBanner();
+    }
+  }
+
+  void _cargarBanner() {
+    // Fire-and-forget: a failure (no plugin channel in `flutter test`, no
+    // fill, offline) leaves `_bannerAd` `null` forever, which keeps this
+    // widget collapsed — exactly the same degrade-to-shrink path a genuine
+    // load failure takes in production. Never throws out of this method.
+    final anuncio = BannerAd(
+      size: AdSize.banner,
+      adUnitId: bannerAdUnitIdPrueba,
+      request: const AdRequest(),
+      listener: BannerAdListener(
+        onAdLoaded: (ad) {
+          if (!mounted) {
+            ad.dispose();
+            return;
+          }
+          setState(() {
+            _bannerAd = ad as BannerAd;
+            _cargado = true;
+          });
+        },
+        onAdFailedToLoad: (ad, error) {
+          ad.dispose();
+        },
+      ),
+    );
+    anuncio.load().catchError((_) {});
+  }
+
+  @override
+  void dispose() {
+    _bannerAd?.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final entitlement = context.watch<EstadoEntitlement>();
+    if (entitlement.esPremium) return const SizedBox.shrink();
+    // Instant vanish-on-purchase (ad-display spec "Ads Vanish Immediately
+    // On Purchase"): even a banner that finished loading BEFORE this
+    // transition is dropped, never shown to a now-premium user.
+    if (!_cargado || _bannerAd == null) return const SizedBox.shrink();
+    final ad = _bannerAd!;
+    return SizedBox(
+      width: ad.size.width.toDouble(),
+      height: ad.size.height.toDouble(),
+      child: AdWidget(ad: ad),
+    );
+  }
+}

lib/widgets/hoja_premium.dart

@@ -0,0 +1,105 @@
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+import '../estado/estado_entitlement.dart';
+import '../l10n/gen/app_localizations.dart';
+import '../tema/pluriwave_tokens.dart';
+import 'pluri_glass_surface.dart';
+import 'pluri_layout.dart';
+
+/// Reusable paywall sheet (Design "File Changes" — `hoja_premium.dart`),
+/// opened from every gated entry point plus the Settings premium row
+/// (freemium-gating spec "Purchase Entry Points At Every Gate Plus
+/// Settings"). Mirrors `FormularioEmisoraPersonalizada`'s bottom-sheet
+/// shape (`ajustes_emisoras_personalizadas.dart`).
+Future<void> mostrarHojaPremium(BuildContext context) {
+  return showModalBottomSheet<void>(
+    context: context,
+    isScrollControlled: true,
+    useSafeArea: true,
+    backgroundColor: Colors.transparent,
+    builder: (_) => const HojaPremium(),
+  );
+}
+
+class HojaPremium extends StatelessWidget {
+  const HojaPremium({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = AppLocalizations.of(context);
+    final entitlement = context.watch<EstadoEntitlement>();
+    final bottom = MediaQuery.of(context).viewInsets.bottom;
+
+    return Padding(
+      padding: EdgeInsets.fromLTRB(
+        PluriLayout.horizontal,
+        PluriLayout.horizontal,
+        PluriLayout.horizontal,
+        PluriLayout.horizontal + bottom,
+      ),
+      child: PluriGlassSurface(
+        padding: const EdgeInsets.all(24),
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: [
+            Row(
+              children: [
+                Icon(
+                  Icons.workspace_premium_rounded,
+                  color: PluriWaveTokens.brand,
+                ),
+                const SizedBox(width: 10),
+                Expanded(
+                  child: Text(
+                    l10n.funcionPremium,
+                    style: Theme.of(context).textTheme.titleLarge?.copyWith(
+                      fontWeight: FontWeight.w900,
+                    ),
+                  ),
+                ),
+              ],
+            ),
+            const SizedBox(height: 20),
+            if (entitlement.esPremium)
+              Padding(
+                key: const ValueKey('hoja-premium-activo'),
+                padding: const EdgeInsets.only(bottom: 12),
+                child: Text(
+                  l10n.equalizerActive,
+                  style: Theme.of(context).textTheme.bodyMedium,
+                ),
+              )
+            else
+              FilledButton.icon(
+                key: const ValueKey('hoja-premium-comprar'),
+                onPressed:
+                    entitlement.compraEnCurso
+                        ? null
+                        : () => entitlement.comprar(),
+                icon:
+                    entitlement.compraEnCurso
+                        ? const SizedBox(
+                          width: 18,
+                          height: 18,
+                          child: CircularProgressIndicator(strokeWidth: 2),
+                        )
+                        : const Icon(Icons.lock_open_rounded),
+                label: Text(l10n.desbloquearPremium),
+              ),
+            const SizedBox(height: 10),
+            OutlinedButton(
+              key: const ValueKey('hoja-premium-restaurar'),
+              onPressed:
+                  entitlement.compraEnCurso
+                      ? null
+                      : () => entitlement.restaurar(),
+              child: Text(l10n.restaurarCompras),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}