fix(buscar): filter pills, Idioma chip, results eyebrow, states screen

Audit 6.2 (t4:292-293): active filter pills are brand-teal tinted with
a 15px close glyph and radius 10 -- was Material's own Chip theming.

Audit 6.3 (t4:294-295): an "Idioma" entry chip is now always reachable
once a search is active -- there was no standalone entry point for
language filtering before (only bundled inside "Filtros"). Opens the
same existing filter sheet rather than a new idioma-only picker.

Audit 6.4 (t4:299): the results-count line now uses eyebrowLabel
styling -- was labelLarge (14/w800).

Audit 13.3/13.4 (t4:649-651): the search-results loading skeleton
gains the missing "BUSCANDO EMISORAS..." eyebrow, and its row gap is
now 4px, not 10.

Audit 13.5/13.6 (t4:657-668): a new purpose-built _TarjetaSinResultados
replaces PluriEmptyState ONLY in the search-no-results branch (that
shared widget is left untouched for its other unrelated call sites --
favorites empty state, the discovery grid). The title now quotes the
typed query ("Sin resultados para <<jazzz>>"), and the clear-filters
pill sits INSIDE the card. New ARB key searchNoResultsForQueryTitle.

Item 6.1 (compact 60px active-search header replacing the persistent
glass pill) is NOT implemented: existing tests confirmed the quality
(bitrate) filter has NO entry point anywhere in the app besides the
header's "Filtros" pill (added first via _abrirYSeleccionarCalidad
while a country filter is ALREADY active, i.e. mid active-search).
Hiding PluriRootHeader during active search would make quality
filtering unreachable -- a real capability regression the task's own
"presentation changes, capability does not" principle forbids.
Re-plumbing where that filter lives is a bigger change than this
visual-fidelity pass should make unilaterally.

lib/pantallas/pantalla_buscar.dart

@@ -253,10 +253,25 @@ class _PantallaBuscarState extends State<PantallaBuscar> {
         }),
     ];
 
-    if (pills.isEmpty && estado.resultados.isEmpty) {
+    // Audit 6.3 (t4:294-295): "Idioma" is an always-reachable entry chip
-      return const SizedBox.shrink();
+    // once a search is active -- there was no standalone entry point for
-    }
+    // language filtering before this (only bundled inside "Filtros").
+    // Opens the SAME existing filter sheet (all 3 sections) rather than a
+    // new idioma-only picker: "Ordenar" is a genuinely separate control
+    // (not part of that sheet), and "Filtros" itself must stay reachable
+    // from the header regardless of active-filter state -- the quality
+    // (bitrate) filter has no OTHER entry point anywhere in the app, so
+    // this chip is additive, not a replacement.
+    final entryChips = <Widget>[
+      ActionChip(
+        label: Text(l10n.searchLanguageFilterLabel),
+        onPressed: _abrirFiltros,
+      ),
+    ];
 
+    // Audit 6.3: entryChips is never empty (always carries "Idioma"), so
+    // this row now always renders while a search is active -- the old
+    // "nothing to show" early return no longer applies.
     return Padding(
       padding: const EdgeInsets.fromLTRB(
         PluriLayout.horizontal,
@@ -267,18 +282,16 @@ class _PantallaBuscarState extends State<PantallaBuscar> {
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
-          if (pills.isNotEmpty)
+          Wrap(spacing: 8, runSpacing: 8, children: [...pills, ...entryChips]),
-            Wrap(spacing: 8, runSpacing: 8, children: pills),
+          if (!estado.cargando && estado.resultados.isNotEmpty) ...[
-          if (pills.isNotEmpty && estado.resultados.isNotEmpty)
             const SizedBox(height: 10),
-          if (!estado.cargando && estado.resultados.isNotEmpty)
             Row(
               children: [
+                // Audit 6.4 (t4:299): eyebrow styling (11/w800/ls.06em) --
+                // was labelLarge (14/w800).
                 Text(
                   l10n.searchResultsCount(estado.resultados.length),
-                  style: theme.textTheme.labelLarge?.copyWith(
+                  style: context.pluriType.eyebrowLabel,
-                    fontWeight: FontWeight.w800,
-                  ),
                 ),
                 const Spacer(),
                 PopupMenuButton<OrdenEmisoras>(
@@ -307,15 +320,27 @@ class _PantallaBuscarState extends State<PantallaBuscar> {
               ],
             ),
           ],
+        ],
       ),
     );
   }
 
+  /// Audit 6.2 (t4:292-293): brand-teal tinted, radius 10, an inline 15px
+  /// close glyph -- was Material's own `Chip` theming.
   Widget _pillFiltro(String label, VoidCallback onDeleted) {
     return Chip(
       label: Text(label),
+      labelStyle: const TextStyle(
+        fontWeight: FontWeight.w800,
+        color: Color(0xFFF2F7FA),
+      ),
+      backgroundColor: PluriWaveTokens.brand.withValues(alpha: 0.2),
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(10),
+        side: BorderSide(color: PluriWaveTokens.brand.withValues(alpha: 0.45)),
+      ),
       onDeleted: onDeleted,
-      deleteIcon: const Icon(Icons.close, size: 18),
+      deleteIcon: const Icon(Icons.close, size: 15),
       visualDensity: VisualDensity.compact,
     );
   }
@@ -521,10 +546,21 @@ class _PantallaBuscarState extends State<PantallaBuscar> {
       return Padding(
         padding: const EdgeInsets.all(PluriLayout.horizontal),
         child: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
           children: [
+            // Audit 13.3 (t4:649): the "BUSCANDO EMISORAS…" eyebrow --
+            // never rendered before.
+            Padding(
+              padding: const EdgeInsets.only(bottom: 10),
+              child: Text(
+                l10n.searchLoadingStationsLabel,
+                style: context.pluriType.eyebrowLabel,
+              ),
+            ),
             for (var i = 0; i < 4; i++) ...[
               const TarjetaEmisoraShimmer(esCompacta: true),
-              if (i < 3) const SizedBox(height: 10),
+              // Audit 13.4 (t4:651): 4px between skeleton rows, not 10.
+              if (i < 3) const SizedBox(height: 4),
             ],
           ],
         ),
@@ -535,36 +571,40 @@ class _PantallaBuscarState extends State<PantallaBuscar> {
 
     if (resultados.isEmpty) {
       final sinFiltros = _controller.text.isEmpty && _filtrosActivosCount == 0;
-      return Column(
+      // Audit 13.5/13.6 (t4:657-668): a purpose-built card for the
-        children: [
+      // search-no-results state -- centred, `listSurface`, the title
-          SizedBox(
+      // QUOTES the typed query, and the clear-filters pill sits INSIDE
-            height: 260,
+      // the card. A NEW widget, not a restyle of the shared
-            child: PluriEmptyState(
+      // `PluriEmptyState` (used by several OTHER unrelated empty states
-              glyph: PluriIconGlyph.search,
+      // across the app -- favorites, the discovery grid -- which this
-              title:
+      // item does not touch).
+      final query = _controller.text.trim();
+      return Padding(
+        padding: const EdgeInsets.symmetric(horizontal: PluriLayout.horizontal),
+        child: _TarjetaSinResultados(
+          titulo:
               sinFiltros
                   ? l10n.searchEmptyTitle
+                  : query.isNotEmpty
+                  ? l10n.searchNoResultsForQueryTitle(query)
                   : l10n.searchNoResultsTitle,
-              subtitle:
+          subtitulo:
               sinFiltros
                   ? l10n.searchEmptySubtitle
                   : l10n.searchNoResultsSubtitle,
-            ),
-          ),
           // task 6.6 / spec "One-Tap Clear-All-Filters on Empty Results":
           // only offered once 1+ pill-filters are active AND the search
           // came back empty — not merely "no query typed yet".
-          if (_filtrosActivosCount > 0)
+          accionQuitarFiltros:
-            Padding(
+              _filtrosActivosCount > 0
-              padding: const EdgeInsets.only(bottom: 16),
+                  ? (
-              child: OutlinedButton(
+                    etiqueta: l10n.searchClearFiltersAction(
-                onPressed: _quitarTodosLosFiltros,
+                      _filtrosActivosCount,
-                child: Text(
-                  l10n.searchClearFiltersAction(_filtrosActivosCount),
                     ),
+                    onTap: _quitarTodosLosFiltros,
+                  )
+                  : null,
         ),
-            ),
-        ],
       );
     }
 
@@ -1213,6 +1253,111 @@ class _ChipShimmer extends StatelessWidget {
   }
 }
 
+/// Audit 13.5/13.6 (t4:657-668): search-no-results card -- centred,
+/// `listSurface`, radius 22 (matches neither of the other 2 named token
+/// radii, so this is a local one-off like `_CeldaExplorarPor`'s own),
+/// with the clear-filters pill living INSIDE the card rather than below
+/// it.
+class _TarjetaSinResultados extends StatelessWidget {
+  const _TarjetaSinResultados({
+    required this.titulo,
+    required this.subtitulo,
+    this.accionQuitarFiltros,
+  });
+
+  final String titulo;
+  final String subtitulo;
+  final ({String etiqueta, VoidCallback onTap})? accionQuitarFiltros;
+
+  static const _radio = 22.0;
+
+  @override
+  Widget build(BuildContext context) {
+    final accion = accionQuitarFiltros;
+    return DecoratedBox(
+      key: const ValueKey('search-no-results-card'),
+      decoration: BoxDecoration(
+        color: PluriWaveTokens.dark.listSurface,
+        borderRadius: BorderRadius.circular(_radio),
+        border: Border.all(color: Colors.white.withValues(alpha: 0.07)),
+      ),
+      child: Padding(
+        padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 26),
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            Icon(
+              Icons.search_off_rounded,
+              size: 40,
+              color: PluriWaveTokens.brand.withValues(alpha: 0.6),
+            ),
+            const SizedBox(height: 12),
+            Text(
+              titulo,
+              textAlign: TextAlign.center,
+              style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w800),
+            ),
+            const SizedBox(height: 5),
+            Text(
+              subtitulo,
+              textAlign: TextAlign.center,
+              style: TextStyle(
+                fontSize: 12.5,
+                height: 1.5,
+                color: Theme.of(
+                  context,
+                ).colorScheme.onSurface.withValues(alpha: 0.6),
+              ),
+            ),
+            if (accion != null) ...[
+              const SizedBox(height: 14),
+              Material(
+                color: Colors.transparent,
+                child: InkWell(
+                  borderRadius: BorderRadius.circular(12),
+                  onTap: accion.onTap,
+                  child: Container(
+                    padding: const EdgeInsets.symmetric(
+                      horizontal: 15,
+                      vertical: 9,
+                    ),
+                    decoration: BoxDecoration(
+                      color: PluriWaveTokens.brand.withValues(alpha: 0.18),
+                      borderRadius: BorderRadius.circular(12),
+                      border: Border.all(
+                        color: PluriWaveTokens.brand.withValues(alpha: 0.4),
+                      ),
+                    ),
+                    child: Row(
+                      mainAxisSize: MainAxisSize.min,
+                      children: [
+                        const Icon(
+                          Icons.filter_alt_off_rounded,
+                          size: 17,
+                          color: PluriWaveTokens.brand,
+                        ),
+                        const SizedBox(width: 7),
+                        Text(
+                          accion.etiqueta,
+                          style: const TextStyle(
+                            fontSize: 12.5,
+                            fontWeight: FontWeight.w800,
+                            color: PluriWaveTokens.brand,
+                          ),
+                        ),
+                      ],
+                    ),
+                  ),
+                ),
+              ),
+            ],
+          ],
+        ),
+      ),
+    );
+  }
+}
+
 /// Audit 3.2 (t4 lines 167-170): one "Explorar por" grid cell — icon,
 /// title (13.5/w800) and subtitle (11/55%). Radius 16 is a local one-off
 /// (like `_errorBanner`'s), matching neither of the 3 named token radii.

test/pantallas/pantalla_buscar_shimmer_test.dart

@@ -89,4 +89,55 @@ void main() {
     expect(find.byType(TarjetaEmisoraShimmer), findsWidgets);
     expect(find.byType(CircularProgressIndicator), findsNothing);
   });
+
+  testWidgets('visual fidelity (audit 13.3/13.4): the "BUSCANDO EMISORAS..." '
+      'eyebrow renders above the loading rows, spaced 4px apart (t4:649-651)', (
+    tester,
+  ) async {
+    final busqueda = _BusquedaCargando();
+    addTearDown(busqueda.dispose);
+    final estado = EstadoRadio(
+      audio: FakeServicioAudio(),
+      favoritos: FakeServicioFavoritos(),
+      radio: FakeServicioRadio(),
+      servicioEcualizador: FakeServicioEcualizador(),
+      servicioGrabacion: FakeServicioGrabacionRadio(),
+      resolverArchivoCustom: () async => throw UnimplementedError(),
+      iniciarAutomaticamente: false,
+    );
+    addTearDown(estado.dispose);
+
+    await tester.pumpWidget(
+      MultiProvider(
+        providers: [
+          ChangeNotifierProvider<EstadoRadio>.value(value: estado),
+          ListenableProvider<EstadoEcualizador>.value(
+            value: estado.ecualizador,
+          ),
+          ListenableProvider<EstadoGrabacion>.value(value: estado.grabacion),
+          ListenableProvider<EstadoBusqueda>.value(value: busqueda),
+        ],
+        child: MaterialApp(
+          locale: const Locale('es'),
+          localizationsDelegates: AppLocalizations.localizationsDelegates,
+          supportedLocales: AppLocalizations.supportedLocales,
+          home: const Scaffold(body: PantallaBuscar()),
+        ),
+      ),
+    );
+    await tester.pump();
+    await tester.enterText(find.byType(SearchBar), 'jazz');
+    await tester.pump();
+
+    final l10n = AppLocalizations.of(
+      tester.element(find.byType(PantallaBuscar)),
+    );
+    expect(find.text(l10n.searchLoadingStationsLabel), findsOneWidget);
+
+    final filas = find.byType(TarjetaEmisoraShimmer);
+    expect(filas, findsWidgets);
+    final primeraAbajo = tester.getBottomLeft(filas.at(0)).dy;
+    final segundaArriba = tester.getTopLeft(filas.at(1)).dy;
+    expect(segundaArriba - primeraAbajo, 4);
+  });
 }

test/pantallas/pantalla_buscar_test.dart

@@ -181,6 +181,101 @@ void main() {
     );
   });
 
+  group('visual fidelity (audit 6.2/6.3/6.4)', () {
+    testWidgets(
+      '6.2: an active filter pill is brand-teal tinted with an inline '
+      'close glyph (t4:292-293)',
+      (tester) async {
+        _setLargeSurfaceSize(tester);
+        final estado = _crearEstado(
+          radio: FakeServicioRadio(
+            busqueda: [emisoraDemo(uuid: 'es-1', nombre: 'Radio Espana')],
+          ),
+        );
+        addTearDown(estado.dispose);
+        await tester.runAsync(estado.inicializar);
+
+        await tester.pumpWidget(_conProviders(estado, _testApp()));
+        await _pumpStableFrame(tester);
+
+        final l10n = _l10nDe(tester);
+        await _abrirYSeleccionarPais(tester, l10n.countrySpain);
+        await _pumpStableFrame(tester);
+
+        final chip = tester.widget<Chip>(
+          find.ancestor(
+            of: find.text(l10n.countrySpain),
+            matching: find.byType(Chip),
+          ),
+        );
+        expect(
+          chip.backgroundColor,
+          const Color(0xFF21D4D9).withValues(alpha: 0.2),
+        );
+        expect(
+          (chip.shape as RoundedRectangleBorder?)?.side.color,
+          const Color(0xFF21D4D9).withValues(alpha: 0.45),
+        );
+      },
+    );
+
+    testWidgets(
+      '6.3: an "Idioma" entry chip is always reachable once a search is '
+      'active, opening the filters sheet (t4:294-295)',
+      (tester) async {
+        _setLargeSurfaceSize(tester);
+        final estado = _crearEstado(
+          radio: FakeServicioRadio(
+            busqueda: [emisoraDemo(uuid: 'r-1', nombre: 'Radio Uno')],
+          ),
+        );
+        addTearDown(estado.dispose);
+        await tester.runAsync(estado.inicializar);
+
+        await tester.pumpWidget(_conProviders(estado, _testApp()));
+        await _pumpStableFrame(tester);
+        await tester.enterText(find.byType(SearchBar), 'radio');
+        await tester.testTextInput.receiveAction(TextInputAction.done);
+        await _pumpStableFrame(tester);
+
+        final l10n = _l10nDe(tester);
+        expect(find.text(l10n.searchLanguageFilterLabel), findsOneWidget);
+
+        await tester.tap(find.text(l10n.searchLanguageFilterLabel));
+        await tester.pumpAndSettle();
+
+        expect(find.text(l10n.searchCountryFilterLabel), findsOneWidget);
+      },
+    );
+
+    testWidgets(
+      '6.4: the results-count eyebrow uses eyebrowLabel styling (t4:299)',
+      (tester) async {
+        _setLargeSurfaceSize(tester);
+        final estado = _crearEstado(
+          radio: FakeServicioRadio(
+            busqueda: [emisoraDemo(uuid: 'r-1', nombre: 'Radio Uno')],
+          ),
+        );
+        addTearDown(estado.dispose);
+        await tester.runAsync(estado.inicializar);
+
+        await tester.pumpWidget(_conProviders(estado, _testApp()));
+        await _pumpStableFrame(tester);
+        await tester.enterText(find.byType(SearchBar), 'radio');
+        await tester.testTextInput.receiveAction(TextInputAction.done);
+        await _pumpStableFrame(tester);
+
+        final l10n = _l10nDe(tester);
+        final texto = tester.widget<Text>(
+          find.text(l10n.searchResultsCount(1)),
+        );
+        expect(texto.style?.fontSize, 11);
+        expect(texto.style?.fontWeight, FontWeight.w800);
+      },
+    );
+  });
+
   group('Buscar — Ordenar (client-side, WU6)', () {
     testWidgets(
       'cada opcion renderizada de Ordenar corresponde a un caso real de '
@@ -774,6 +869,44 @@ void main() {
   // Hazard: `pumpAndSettle()` never terminates while this card's rotating
   // ring animates -- every assertion below uses a bounded `pump()` once
   // `reconectando` is emitted, never `_pumpStableFrame`'s `pumpAndSettle`.
+  group('visual fidelity (audit 13.5/13.6)', () {
+    testWidgets(
+      '13.5/13.6: the no-results card quotes the query, and the "clear '
+      'filters" pill sits INSIDE the same card (t4:657-663)',
+      (tester) async {
+        _setLargeSurfaceSize(tester);
+        final estado = _crearEstado(radio: FakeServicioRadio(busqueda: []));
+        addTearDown(estado.dispose);
+        await tester.runAsync(estado.inicializar);
+
+        await tester.pumpWidget(_conProviders(estado, _testApp()));
+        await _pumpStableFrame(tester);
+        await _abrirYSeleccionarPais(tester, _l10nDe(tester).countrySpain);
+        await _pumpStableFrame(tester);
+        await tester.enterText(find.byType(SearchBar), 'jazzz');
+        await tester.testTextInput.receiveAction(TextInputAction.done);
+        await _pumpStableFrame(tester);
+
+        final l10n = _l10nDe(tester);
+        expect(
+          find.text(l10n.searchNoResultsForQueryTitle('jazzz')),
+          findsOneWidget,
+        );
+
+        final tarjeta = find.byKey(const ValueKey('search-no-results-card'));
+        expect(tarjeta, findsOneWidget);
+        expect(
+          find.descendant(
+            of: tarjeta,
+            matching: find.text(l10n.searchClearFiltersAction(1)),
+          ),
+          findsOneWidget,
+          reason: 't4:667 the clear-filters pill sits INSIDE the card',
+        );
+      },
+    );
+  });
+
   group('Item 25 -- reconnect card (audit 13.2)', () {
     testWidgets(
       'shows the station name, "Reconectando...", and a stop button while '