feat(escuchar): replace discovery browser with embedded player and favorites grid

Restructures PantallaInicio's top of screen: a new _EscucharHero
(square art, live/offline pill, VisualizadorAudio at barras: 30 /
altura: 26 / color: liveGreen, a 5-action transport row - favorite,
EQ toggle, stop, play/pause, sleep - plus a tool-tray entry chip
opening the full player) replaces the old PluriScreenHeader hero, and
a new "Tus emisoras" section (favorites preview, capped, "Ver todas")
follows it. Per design ADR-7, EstadoRadio stays the single source of
truth: the hero is a StatelessWidget with no cached fields, reading
emisoraActual via context.select (uuid-based equality scopes rebuilds
to real station changes) and the fast-changing playback status via
StreamBuilder, the same pattern _Controles/MiniReproductor already
use. The still-present discovery sections (_seccionCercanas onward,
including the old grid) are deliberately left in place - WU6
relocates them to Buscar and deletes them from here; removing them
now would leave that content nowhere until WU6 lands.

MiniReproductor gains a `visible` parameter (default true) and a
measured `static const double altura`. app.dart passes
`visible: indice != RaizPluriWave.escuchar.index`, hiding it visually
only (SizedBox.shrink()) while Escuchar is active, since the hero
already shows the same station - the State stays mounted so its
didChangeDependencies side effect (configurarLocalizaciones, S3-R3)
keeps running regardless of tab. altura was measured empirically
(72.0, via tester.getSize) rather than guessed, backing a new derived
PluriLayout.escucharBottomChromeInset constant now wired into
PantallaInicio's own bottom padding.

"Ver todas" switches roots via EstadoNavegacionRaiz.irA(favoritos),
verified via a NavigatorObserver asserting the push count is
unchanged (switches tabs, does not push).

Fixed a pre-existing test-infrastructure gap while writing the
anti-cache test: no test in this codebase had ever exercised
ServicioAudio.androidAudioSessionIdStream against a bare
FakeServicioAudio (pantalla_reproductor.dart has always read it but
has no test file at all) - the real getter needs registrarHandler()
(main.dart, production only) and threw otherwise. Added an empty
stream override to FakeServicioAudio, matching VisualizadorAudio's
own documented no-native-session fallback.

Tests: 614 -> 618 (2 skipped, unchanged). flutter analyze unchanged
at 1 pre-existing info. git diff empty for visualizador_audio.dart
and estado_radio.dart - this WU touches neither.

lib/l10n/app_en.arb

@@ -336,6 +336,11 @@
     }
   },
   "qualityHd": "HD quality",
+  "yourStationsTitle": "Your stations",
+  "seeAllAction": "See all",
+  "openFullPlayerTooltip": "Open full player",
+  "nothingPlayingTitle": "Nothing playing yet",
+  "nothingPlayingSubtitle": "Pick a station from Your stations or search to start.",
   "nearYou": "Near you",
   "nearYouInCountry": "Near you · {country}",
   "@nearYouInCountry": {

lib/l10n/app_es.arb

@@ -336,6 +336,11 @@
     }
   },
   "qualityHd": "Calidad HD",
+  "yourStationsTitle": "Tus emisoras",
+  "seeAllAction": "Ver todas",
+  "openFullPlayerTooltip": "Abrir reproductor completo",
+  "nothingPlayingTitle": "Todavía no estás escuchando nada",
+  "nothingPlayingSubtitle": "Elegí una emisora de Tus emisoras o buscá una para empezar.",
   "nearYou": "Cerca de vos",
   "nearYouInCountry": "Cerca de vos · {country}",
   "@nearYouInCountry": {

lib/l10n/gen/app_localizations.dart

@@ -1270,6 +1270,36 @@ abstract class AppLocalizations {
   /// **'Calidad HD'**
   String get qualityHd;
 
+  /// No description provided for @yourStationsTitle.
+  ///
+  /// In es, this message translates to:
+  /// **'Tus emisoras'**
+  String get yourStationsTitle;
+
+  /// No description provided for @seeAllAction.
+  ///
+  /// In es, this message translates to:
+  /// **'Ver todas'**
+  String get seeAllAction;
+
+  /// No description provided for @openFullPlayerTooltip.
+  ///
+  /// In es, this message translates to:
+  /// **'Abrir reproductor completo'**
+  String get openFullPlayerTooltip;
+
+  /// No description provided for @nothingPlayingTitle.
+  ///
+  /// In es, this message translates to:
+  /// **'Todavía no estás escuchando nada'**
+  String get nothingPlayingTitle;
+
+  /// No description provided for @nothingPlayingSubtitle.
+  ///
+  /// In es, this message translates to:
+  /// **'Elegí una emisora de Tus emisoras o buscá una para empezar.'**
+  String get nothingPlayingSubtitle;
+
   /// No description provided for @nearYou.
   ///
   /// In es, this message translates to:

lib/l10n/gen/app_localizations_ar.dart

@@ -658,6 +658,22 @@ class AppLocalizationsAr extends AppLocalizations {
   @override
   String get qualityHd => 'جودة HD';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'بالقرب منك';
 

lib/l10n/gen/app_localizations_bn.dart

@@ -662,6 +662,22 @@ class AppLocalizationsBn extends AppLocalizations {
   @override
   String get qualityHd => 'HD গুণমান';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'আপনার কাছাকাছি';
 

lib/l10n/gen/app_localizations_de.dart

@@ -665,6 +665,22 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get qualityHd => 'HD-Qualität';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'In deiner Nähe';
 

lib/l10n/gen/app_localizations_en.dart

@@ -659,6 +659,22 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get qualityHd => 'HD quality';
 
+  @override
+  String get yourStationsTitle => 'Your stations';
+
+  @override
+  String get seeAllAction => 'See all';
+
+  @override
+  String get openFullPlayerTooltip => 'Open full player';
+
+  @override
+  String get nothingPlayingTitle => 'Nothing playing yet';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Pick a station from Your stations or search to start.';
+
   @override
   String get nearYou => 'Near you';
 

lib/l10n/gen/app_localizations_es.dart

@@ -663,6 +663,22 @@ class AppLocalizationsEs extends AppLocalizations {
   @override
   String get qualityHd => 'Calidad HD';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'Cerca de vos';
 

lib/l10n/gen/app_localizations_fr.dart

@@ -667,6 +667,22 @@ class AppLocalizationsFr extends AppLocalizations {
   @override
   String get qualityHd => 'Qualité HD';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'Près de vous';
 

lib/l10n/gen/app_localizations_hi.dart

@@ -660,6 +660,22 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get qualityHd => 'HD गुणवत्ता';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'आपके पास';
 

lib/l10n/gen/app_localizations_id.dart

@@ -661,6 +661,22 @@ class AppLocalizationsId extends AppLocalizations {
   @override
   String get qualityHd => 'Kualitas HD';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'Di dekat Anda';
 

lib/l10n/gen/app_localizations_it.dart

@@ -663,6 +663,22 @@ class AppLocalizationsIt extends AppLocalizations {
   @override
   String get qualityHd => 'Qualità HD';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'Vicino a te';
 

lib/l10n/gen/app_localizations_ja.dart

@@ -640,6 +640,22 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get qualityHd => 'HD品質';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => '近く';
 

lib/l10n/gen/app_localizations_pt.dart

@@ -662,6 +662,22 @@ class AppLocalizationsPt extends AppLocalizations {
   @override
   String get qualityHd => 'Qualidade HD';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'Perto de você';
 

lib/l10n/gen/app_localizations_ru.dart

@@ -663,6 +663,22 @@ class AppLocalizationsRu extends AppLocalizations {
   @override
   String get qualityHd => 'HD-качество';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => 'Рядом с вами';
 

lib/l10n/gen/app_localizations_zh.dart

@@ -637,6 +637,22 @@ class AppLocalizationsZh extends AppLocalizations {
   @override
   String get qualityHd => '高清音质';
 
+  @override
+  String get yourStationsTitle => 'Tus emisoras';
+
+  @override
+  String get seeAllAction => 'Ver todas';
+
+  @override
+  String get openFullPlayerTooltip => 'Abrir reproductor completo';
+
+  @override
+  String get nothingPlayingTitle => 'Todavía no estás escuchando nada';
+
+  @override
+  String get nothingPlayingSubtitle =>
+      'Elegí una emisora de Tus emisoras o buscá una para empezar.';
+
   @override
   String get nearYou => '你附近';