fix(ecualizador): header switch, banner radius, preset chips, glow thumb

Audit 11.1 (t4:566): the master enable switch moves to
PluriPushScaffold's header actions -- was the body's first
SwitchListTile row. Its realtime/pending explainer subtitle stays
behind as a plain caption so no information is lost.

Audit 11.2 (t4:571): explainer banner radius is 16 (a local one-off,
matching neither of the 3 named tokens), not radiusSm's 14.

Audit 11.3 (t4:574-577): preset chips are solid brand-teal with dark
text when active, listSurface + a faint border when not -- was
Material's own ChoiceChip theming (primaryContainer/grey).

Audit 11.5 (t4:585): band sliders use a new 20x20 _GlowSliderThumbShape
(brand-teal blurred glow + solid thumb), replacing the Material
default round thumb.

Audit 11.7 (t4:584): the dB label is brand teal at 90% alpha, not
liveGreen -- a leftover wrong colour family 11.6's slider-only fix
never touched.

Updated 2 pre-existing tests (pantalla_ajustes_ecualizador_test.dart,
pantalla_ajustes_test.dart) to locate the enable switch by key instead
of by the "Enable equalizer" text it no longer renders next to.

lib/pantallas/ajustes/pantalla_ajustes_ecualizador.dart

@@ -8,6 +8,7 @@ import '../../estado/estado_radio.dart';
 import '../../l10n/gen/app_localizations.dart';
 import '../../modelos/preset_ecualizador.dart';
 import '../../tema/pluriwave_theme.dart';
+import '../../tema/pluriwave_tokens.dart';
 import '../../widgets/ecualizador_widget.dart';
 import '../../widgets/pluri_glass_surface.dart';
 import '../../widgets/pluri_layout.dart';
@@ -36,13 +37,33 @@ class PantallaAjustesEcualizador extends StatelessWidget {
   const PantallaAjustesEcualizador({super.key});
 
   @override
-  Widget build(BuildContext context) => PluriPushScaffold(
+  Widget build(BuildContext context) {
+    // Audit 11.1 (t4 line 566): the master enable switch lives in the
+    // HEADER, not as the body's first row -- read here (a second,
+    // cheap watch alongside _CuerpoEcualizadorState's own Consumer2)
+    // purely to feed PluriPushScaffold.actions.
+    final eq = context.watch<EstadoEcualizador>();
+    return PluriPushScaffold(
       title: AppLocalizations.of(context).equalizerTitle,
+      actions: [
+        Padding(
+          padding: const EdgeInsets.only(right: 8),
+          child: Switch(
+            key: const ValueKey('eq-master-switch'),
+            value: eq.activo,
+            onChanged: eq.cambiarActivo,
+            // t4 line 569: brand-teal track, white thumb -- the default
+            // Material thumb colour already renders white when "on".
+            activeTrackColor: PluriWaveTokens.brand,
+          ),
+        ),
+      ],
       body: ListView(
         padding: PluriLayout.pageContentPadding,
         children: const [_CuerpoEcualizador()],
       ),
     );
+  }
 }
 
 class _CuerpoEcualizador extends StatefulWidget {
@@ -83,17 +104,18 @@ class _CuerpoEcualizadorState extends State<_CuerpoEcualizador> {
         return Column(
           crossAxisAlignment: CrossAxisAlignment.stretch,
           children: [
-            SwitchListTile.adaptive(
+            // Audit 11.1 (t4 line 566): the enable switch itself now lives
-              contentPadding: EdgeInsets.zero,
+            // in PluriPushScaffold's header (see PantallaAjustesEcualizador
-              title: Text(l10n.equalizerEnable),
+            // above) -- this stays behind only as the explanatory caption
-              subtitle: Text(
+            // the old SwitchListTile's subtitle carried, so that
+            // information is not lost.
+            Text(
               disponible
                   ? l10n.equalizerRealtimeSubtitle
                   : l10n.equalizerPendingSubtitle,
+              style: Theme.of(ctx).textTheme.bodySmall,
             ),
-              value: eq.activo,
+            const SizedBox(height: 12),
-              onChanged: eq.cambiarActivo,
-            ),
             if (mostrarModoPorEmisora) ...[
               const SizedBox(height: 8),
               SwitchListTile.adaptive(
@@ -164,6 +186,12 @@ class _BannerExplicacionBase extends StatelessWidget {
 
   final AppLocalizations l10n;
 
+  /// Audit 11.2 (t4 line 571): 16 -- doesn't match any of
+  /// [PluriWaveTokens]'s three named radii (14/18/30), so this stays a
+  /// local one-off constant (same precedent as `_stopButtonRadius` in
+  /// `pantalla_alarma_sonando.dart`).
+  static const _bannerRadius = 16.0;
+
   @override
   Widget build(BuildContext context) {
     final tokens = context.pluriTokens;
@@ -172,7 +200,7 @@ class _BannerExplicacionBase extends StatelessWidget {
       padding: const EdgeInsets.all(14),
       decoration: BoxDecoration(
         color: tokens.liveGreen.withValues(alpha: 0.09),
-        borderRadius: BorderRadius.circular(tokens.radiusSm),
+        borderRadius: BorderRadius.circular(_bannerRadius),
         border: Border.all(color: tokens.liveGreen.withValues(alpha: 0.26)),
       ),
       child: Row(

lib/widgets/ecualizador_widget.dart

@@ -113,6 +113,10 @@ class _EcualizadorWidgetState extends State<EcualizadorWidget> {
                                       theme.colorScheme.surfaceContainerHighest,
                                   overlayColor: PluriWaveTokens.brand
                                       .withValues(alpha: 0.15),
+                                  // Audit 11.5 (t4 line 585): a 20x20 thumb
+                                  // with a 14px brand-teal glow -- was the
+                                  // Material default round thumb shape.
+                                  thumbShape: const _GlowSliderThumbShape(),
                                 ),
                                 child: Slider(
                                   value: _bandas[i],
@@ -130,8 +134,12 @@ class _EcualizadorWidgetState extends State<EcualizadorWidget> {
                         ),
                         Text(
                           '${_bandas[i].toStringAsFixed(1)}dB',
+                          // Audit 11.7 (t4 line 584): the prototype's dB
+                          // label is brand teal at 90% alpha -- `liveGreen`
+                          // is the LIVE-badge colour, an unrelated wrong
+                          // family untouched by 11.6's slider-only fix.
                           style: theme.textTheme.labelSmall?.copyWith(
-                            color: tokens.liveGreen,
+                            color: PluriWaveTokens.brand.withValues(alpha: 0.9),
                             fontWeight: FontWeight.w700,
                           ),
                         ),
@@ -154,6 +162,50 @@ class _EcualizadorWidgetState extends State<EcualizadorWidget> {
   }
 }
 
+/// Audit 11.5 (t4 line 585): `width:6px;border-radius:3px` track with a
+/// `20x20` thumb carrying `box-shadow:0 0 14px rgba(33,212,217,.6)` --
+/// Material's stock `RoundSliderThumbShape` has neither the exact size nor
+/// a coloured glow (its own elevation shadow is a neutral drop shadow, not
+/// brand-tinted). Paints a soft blurred glow first, then the solid thumb
+/// on top, both centred on the slider's reported thumb position.
+class _GlowSliderThumbShape extends SliderComponentShape {
+  const _GlowSliderThumbShape();
+
+  static const _radius = 10.0;
+
+  @override
+  Size getPreferredSize(bool isEnabled, bool isDiscrete) =>
+      const Size(_radius * 2, _radius * 2);
+
+  @override
+  void paint(
+    PaintingContext context,
+    Offset center, {
+    required Animation<double> activationAnimation,
+    required Animation<double> enableAnimation,
+    required bool isDiscrete,
+    required TextPainter labelPainter,
+    required RenderBox parentBox,
+    required SliderThemeData sliderTheme,
+    required TextDirection textDirection,
+    required double value,
+    required double textScaleFactor,
+    required Size sizeWithOverflow,
+  }) {
+    final canvas = context.canvas;
+    final color = sliderTheme.thumbColor ?? PluriWaveTokens.brand;
+
+    final glowPaint =
+        Paint()
+          ..color = color.withValues(alpha: 0.6)
+          ..maskFilter = const MaskFilter.blur(BlurStyle.normal, 7);
+    canvas.drawCircle(center, _radius + 4, glowPaint);
+
+    final thumbPaint = Paint()..color = color;
+    canvas.drawCircle(center, _radius, thumbPaint);
+  }
+}
+
 String _nombrePreset(AppLocalizations l10n, String nombre) {
   return switch (nombre) {
     'Flat' => l10n.equalizerPresetFlat,
@@ -188,7 +240,6 @@ class PresetsEcualizadorWidget extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final theme = Theme.of(context);
     final l10n = AppLocalizations.of(context);
     final todos = [...PresetEcualizador.presets, ...personalizados];
     return Wrap(
@@ -197,13 +248,32 @@ class PresetsEcualizadorWidget extends StatelessWidget {
       children:
           todos.map((p) {
             final selected = p.nombre == presetActual.nombre;
+            // Audit 11.3 (t4 lines 574-577): a solid brand-teal chip with
+            // dark text when active, `listSurface` + a faint border when
+            // not -- was Material's own `ChoiceChip` theming
+            // (`primaryContainer` selected / translucent grey unselected).
             return ChoiceChip(
               label: Text(_nombrePreset(l10n, p.nombre)),
+              labelStyle: TextStyle(
+                fontWeight: FontWeight.w800,
+                color:
+                    selected
+                        ? const Color(0xFF062126)
+                        : const Color(0xFFF2F7FA),
+              ),
               selected: selected,
               showCheckmark: false,
-              selectedColor: theme.colorScheme.primaryContainer,
+              selectedColor: PluriWaveTokens.brand,
-              backgroundColor: theme.colorScheme.surfaceContainerHighest
+              backgroundColor: PluriWaveTokens.dark.listSurface,
-                  .withValues(alpha: 0.32),
+              side: BorderSide(
+                color:
+                    selected
+                        ? Colors.transparent
+                        : Colors.white.withValues(alpha: 0.09),
+              ),
+              shape: RoundedRectangleBorder(
+                borderRadius: BorderRadius.circular(12),
+              ),
               onSelected: (_) => onSeleccionar(p),
             );
           }).toList(),

test/pantallas/ajustes/pantalla_ajustes_ecualizador_test.dart

@@ -9,6 +9,7 @@ import 'package:pluriwave/modelos/dispositivo_audio.dart';
 import 'package:pluriwave/modelos/emisora.dart';
 import 'package:pluriwave/modelos/preset_ecualizador.dart';
 import 'package:pluriwave/pantallas/ajustes/pantalla_ajustes_ecualizador.dart';
+import 'package:pluriwave/tema/pluriwave_tokens.dart';
 import 'package:pluriwave/widgets/ecualizador_widget.dart';
 import 'package:pluriwave/widgets/pluri_glass_surface.dart';
 import 'package:pluriwave/widgets/pluri_push_scaffold.dart';
@@ -119,9 +120,8 @@ void main() {
     expect((appBar.title as Text).data, equals('Equalizer'));
   });
 
-  testWidgets('moved control still responds: enable switch toggles activo', (
+  testWidgets('moved control still responds: enable switch toggles activo '
-    tester,
+      '(audit 11.1: now in the header, t4 line 566)', (tester) async {
-  ) async {
     _suppressListTileInkAssertion();
     final estado = await crearEstado();
     addTearDown(estado.dispose);
@@ -130,7 +130,7 @@ void main() {
     await tester.pumpAndSettle();
 
     final before = estado.ecualizador.activo;
-    await tester.tap(find.text('Enable equalizer'));
+    await tester.tap(find.byKey(const ValueKey('eq-master-switch')));
     await tester.pumpAndSettle();
 
     expect(estado.ecualizador.activo, equals(!before));
@@ -447,6 +447,74 @@ void main() {
       },
     );
 
+    testWidgets(
+      'visual fidelity (audit 11.1): the master switch is a header action, '
+      'not the body\'s first row (t4 line 566)',
+      (tester) async {
+        _suppressListTileInkAssertion();
+        final estado = await crearEstado();
+        addTearDown(estado.dispose);
+
+        await tester.pumpWidget(buildScreen(estado));
+        await tester.pumpAndSettle();
+
+        expect(
+          find.descendant(
+            of: find.byType(AppBar),
+            matching: find.byKey(const ValueKey('eq-master-switch')),
+          ),
+          findsOneWidget,
+          reason: 'the master switch lives in the AppBar, not the body',
+        );
+        expect(
+          find.descendant(
+            of: find.byType(ListView),
+            matching: find.byKey(const ValueKey('eq-master-switch')),
+          ),
+          findsNothing,
+        );
+      },
+    );
+
+    testWidgets(
+      'visual fidelity (audit 11.2): the explainer banner radius is 16, '
+      'not radiusSm\'s 14 (t4 line 571)',
+      (tester) async {
+        _suppressListTileInkAssertion();
+        final estado = await crearEstado();
+        addTearDown(estado.dispose);
+
+        await tester.pumpWidget(buildScreen(estado));
+        await tester.pumpAndSettle();
+
+        final banner = tester.widget<Container>(
+          find.byKey(const Key('eq-base-explainer-banner')),
+        );
+        final decoration = banner.decoration as BoxDecoration;
+        expect(
+          (decoration.borderRadius as BorderRadius).topLeft,
+          const Radius.circular(16),
+        );
+      },
+    );
+
+    testWidgets('visual fidelity (audit 11.3): the active preset chip is solid '
+        'brand teal with dark text (t4 lines 574-577)', (tester) async {
+      _suppressListTileInkAssertion();
+      final estado = await crearEstado();
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(buildScreen(estado));
+      await tester.pumpAndSettle();
+
+      final chip = tester.widget<ChoiceChip>(
+        find.widgetWithText(ChoiceChip, 'Flat'),
+      );
+      expect(chip.selected, isTrue);
+      expect(chip.selectedColor, PluriWaveTokens.brand);
+      expect(chip.labelStyle?.color, const Color(0xFF062126));
+    });
+
     testWidgets(
       'Guardar como preset with a whitespace-only name shows the same validation message',
       (tester) async {

test/pantallas/pantalla_ajustes_test.dart

@@ -162,9 +162,10 @@ void main() {
       await pumpStable(tester);
 
       // Pushed, not index-switched: exactly one PluriPushScaffold now exists,
-      // and its moved control (the enable switch) is reachable.
+      // and its moved control (the enable switch, audit 11.1 -- now a
+      // header action, t4 line 566) is reachable.
       expect(find.byType(PluriPushScaffold), findsOneWidget);
-      expect(find.text('Enable equalizer'), findsOneWidget);
+      expect(find.byKey(const ValueKey('eq-master-switch')), findsOneWidget);
     });
 
     testWidgets('tapping the Orden de listas row pushes its detail screen', (

test/widgets/ecualizador_widget_test.dart

@@ -136,4 +136,30 @@ void main() {
           'EQ bands with brand teal #21D4D9 (t4 line 585)',
     );
   });
+
+  testWidgets(
+    'visual fidelity (audit 11.5): the thumb is a 20x20 custom glow shape, '
+    'not the Material default (t4 line 585)',
+    (tester) async {
+      await tester.pumpWidget(buildWidget());
+
+      final tema = SliderTheme.of(tester.element(find.byType(Slider).first));
+      final size = tema.thumbShape?.getPreferredSize(true, false);
+
+      expect(
+        size,
+        const Size(20, 20),
+        reason: 't4 line 585: a 20x20 thumb with a 14px brand-teal glow',
+      );
+    },
+  );
+
+  testWidgets('visual fidelity (audit 11.7): the dB label is brand teal, not '
+      'liveGreen (t4 line 584)', (tester) async {
+    await tester.pumpWidget(buildWidget());
+
+    final label = tester.widget<Text>(find.text('0.0dB').first);
+    expect(label.style?.color, PluriWaveTokens.brand.withValues(alpha: 0.9));
+    expect(label.style?.color, isNot(PluriWaveTokens.dark.liveGreen));
+  });
 }