fix(chrome): drop the global AppBar, give each root its own title row

The prototype (t4) draws no global app bar anywhere: every root paints
a plain ~56px title row inside its own content instead (Alarmas line
325, Ajustes line 511, Explorar line 641). app.dart wrapped every tab
in PluriWaveScaffold(appBar: AppBar(title: Text(appTitle), ...)),
adding 56dp of chrome and a "PluriWave" title the prototype never
shows.

Add PluriRootHeader, a shared 56px title-row widget reused by all 5
roots. Extract app.dart's old _mostrarTimerDialog (only reachable from
the removed AppBar action) into a free function,
showPluriSleepTimerSheet, so every root's header can open the same
sheet directly and the sleep-timer feature stays reachable from every
tab with no behaviour change.

S1, Tier 1 visual-fidelity pass (audit id 2521).

lib/app.dart

@@ -217,16 +217,6 @@ class _PaginaPrincipalState extends State<_PaginaPrincipal>
     final indice = navegacion.indice;
 
     return PluriWaveScaffold(
-      appBar: AppBar(
-        title: Text(l10n.appTitle),
-        actions: [
-          IconButton(
-            icon: const Icon(Icons.bedtime_outlined),
-            tooltip: l10n.sleepTimer,
-            onPressed: () => _mostrarTimerDialog(context),
-          ),
-        ],
-      ),
       body: SafeArea(
         top: false,
         child: AnimatedSwitcher(
@@ -423,253 +413,4 @@ class _PaginaPrincipalState extends State<_PaginaPrincipal>
       }
     }
   }
-
-  void _mostrarTimerDialog(BuildContext context) {
-    showModalBottomSheet(
-      context: context,
-      showDragHandle: true,
-      builder:
-          (ctx) => Consumer<EstadoRadio>(
-            builder:
-                (ctx, estado, _) => SafeArea(
-                  child: Padding(
-                    padding: PluriLayout.sheetPadding,
-                    child: Column(
-                      mainAxisSize: MainAxisSize.min,
-                      crossAxisAlignment: CrossAxisAlignment.start,
-                      children: [
-                        Text(
-                          AppLocalizations.of(ctx).sleepTimer,
-                          style: Theme.of(ctx).textTheme.titleLarge,
-                        ),
-                        const SizedBox(height: PluriLayout.sectionGap),
-                        Text(
-                          AppLocalizations.of(ctx).sleepTimerDescription,
-                          style: Theme.of(ctx).textTheme.bodySmall,
-                        ),
-                        const SizedBox(height: PluriLayout.panelGap),
-                        if (estado.timer.activo)
-                          StreamBuilder<Duration>(
-                            stream: estado.timer.tiempoRestanteStream,
-                            builder: (ctx, snap) {
-                              final restante =
-                                  snap.data ?? estado.timer.tiempoRestante;
-                              return Column(
-                                crossAxisAlignment: CrossAxisAlignment.stretch,
-                                children: [
-                                  Text(
-                                    _formatearDuracionTimer(
-                                      AppLocalizations.of(ctx),
-                                      restante,
-                                    ),
-                                    style:
-                                        Theme.of(ctx).textTheme.headlineMedium,
-                                  ),
-                                  const SizedBox(
-                                    height: PluriLayout.compactGap,
-                                  ),
-                                  FilledButton.tonal(
-                                    onPressed: () {
-                                      estado.cancelarTimer();
-                                      Navigator.pop(ctx);
-                                    },
-                                    child: Text(
-                                      AppLocalizations.of(ctx).cancelTimer,
-                                    ),
-                                  ),
-                                ],
-                              );
-                            },
-                          )
-                        else
-                          Wrap(
-                            spacing: PluriLayout.compactGap,
-                            runSpacing: PluriLayout.compactGap,
-                            children: [
-                              for (final segundos
-                                  in estado.timerSuenoPresetsSegundos)
-                                ActionChip(
-                                  label: Text(
-                                    _formatearDuracionTimer(
-                                      AppLocalizations.of(ctx),
-                                      Duration(seconds: segundos),
-                                    ),
-                                  ),
-                                  onPressed: () {
-                                    estado.iniciarTimerDuracion(
-                                      Duration(seconds: segundos),
-                                    );
-                                    Navigator.pop(ctx);
-                                  },
-                                ),
-                              ActionChip(
-                                avatar: const Icon(
-                                  Icons.tune_rounded,
-                                  size: 18,
-                                ),
-                                label: Text(
-                                  AppLocalizations.of(ctx).optionOther,
-                                ),
-                                onPressed: () async {
-                                  final duracion =
-                                      await _pedirDuracionPersonalizada(ctx);
-                                  if (duracion == null || !ctx.mounted) return;
-                                  estado.iniciarTimerDuracion(duracion);
-                                  Navigator.pop(ctx);
-                                },
-                              ),
-                            ],
-                          ),
-                      ],
-                    ),
-                  ),
-                ),
-          ),
-    );
-  }
-
-  Future<Duration?> _pedirDuracionPersonalizada(BuildContext context) {
-    return showModalBottomSheet<Duration>(
-      context: context,
-      isScrollControlled: true,
-      showDragHandle: true,
-      builder: (ctx) => const _TimerPersonalizadoSheet(),
-    );
-  }
-}
-
-String _formatearDuracionTimer(AppLocalizations l10n, Duration duracion) {
-  final horas = duracion.inHours;
-  final minutos = duracion.inMinutes.remainder(60);
-  final segundos = duracion.inSeconds.remainder(60);
-  if (horas > 0) {
-    return l10n.durationHoursMinutesSeconds(
-      horas,
-      minutos.toString().padLeft(2, '0'),
-      segundos.toString().padLeft(2, '0'),
-    );
-  }
-  if (minutos > 0) {
-    return segundos == 0
-        ? l10n.durationMinutesOnly(minutos)
-        : l10n.durationMinutesSeconds(
-          minutos,
-          segundos.toString().padLeft(2, '0'),
-        );
-  }
-  return l10n.durationSecondsOnly(segundos);
-}
-
-class _TimerPersonalizadoSheet extends StatefulWidget {
-  const _TimerPersonalizadoSheet();
-
-  @override
-  State<_TimerPersonalizadoSheet> createState() =>
-      _TimerPersonalizadoSheetState();
-}
-
-class _TimerPersonalizadoSheetState extends State<_TimerPersonalizadoSheet> {
-  final _horasCtrl = TextEditingController();
-  final _minutosCtrl = TextEditingController(text: '15');
-  final _segundosCtrl = TextEditingController();
-  bool _guardarPreset = true;
-
-  @override
-  void dispose() {
-    _horasCtrl.dispose();
-    _minutosCtrl.dispose();
-    _segundosCtrl.dispose();
-    super.dispose();
-  }
-
-  int _leer(TextEditingController ctrl) => int.tryParse(ctrl.text.trim()) ?? 0;
-
-  Future<void> _confirmar() async {
-    final duracion = Duration(
-      hours: _leer(_horasCtrl),
-      minutes: _leer(_minutosCtrl),
-      seconds: _leer(_segundosCtrl),
-    );
-    if (duracion <= Duration.zero) {
-      ScaffoldMessenger.of(context).showSnackBar(
-        SnackBar(
-          content: Text(AppLocalizations.of(context).durationGreaterThanZero),
-        ),
-      );
-      return;
-    }
-    if (_guardarPreset) {
-      await context.read<EstadoRadio>().agregarTimerSuenoPreset(duracion);
-    }
-    if (mounted) Navigator.pop(context, duracion);
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    final bottom = MediaQuery.viewInsetsOf(context).bottom;
-    return SafeArea(
-      child: Padding(
-        padding: EdgeInsets.fromLTRB(18, 0, 18, 18 + bottom),
-        child: Column(
-          mainAxisSize: MainAxisSize.min,
-          crossAxisAlignment: CrossAxisAlignment.stretch,
-          children: [
-            Text(
-              AppLocalizations.of(context).customDurationTitle,
-              style: Theme.of(context).textTheme.titleLarge,
-            ),
-            const SizedBox(height: PluriLayout.sectionGap),
-            Row(
-              children: [
-                Expanded(
-                  child: _campoTiempo(
-                    _horasCtrl,
-                    AppLocalizations.of(context).hoursLabel,
-                  ),
-                ),
-                const SizedBox(width: PluriLayout.compactGap),
-                Expanded(
-                  child: _campoTiempo(
-                    _minutosCtrl,
-                    AppLocalizations.of(context).minutesLabel,
-                  ),
-                ),
-                const SizedBox(width: PluriLayout.compactGap),
-                Expanded(
-                  child: _campoTiempo(
-                    _segundosCtrl,
-                    AppLocalizations.of(context).secondsLabel,
-                  ),
-                ),
-              ],
-            ),
-            const SizedBox(height: PluriLayout.compactGap),
-            SwitchListTile.adaptive(
-              contentPadding: EdgeInsets.zero,
-              title: Text(AppLocalizations.of(context).saveQuickAccess),
-              value: _guardarPreset,
-              onChanged: (value) => setState(() => _guardarPreset = value),
-            ),
-            const SizedBox(height: PluriLayout.sectionGap),
-            FilledButton.icon(
-              icon: const Icon(Icons.bedtime_rounded),
-              label: Text(AppLocalizations.of(context).startTimer),
-              onPressed: _confirmar,
-            ),
-          ],
-        ),
-      ),
-    );
-  }
-
-  Widget _campoTiempo(TextEditingController controller, String label) {
-    return TextField(
-      controller: controller,
-      keyboardType: TextInputType.number,
-      decoration: InputDecoration(
-        labelText: label,
-        border: const OutlineInputBorder(),
-      ),
-    );
-  }
 }

lib/pantallas/pantalla_ajustes.dart

@@ -5,6 +5,8 @@ import '../widgets/pluri_icon.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_premium_widgets.dart';
 import '../widgets/pluri_push_scaffold.dart';
+import '../widgets/pluri_root_header.dart';
+import '../widgets/pluri_sleep_timer_sheet.dart';
 import 'ajustes/pantalla_ajustes_backup.dart';
 import 'ajustes/pantalla_ajustes_ecualizador.dart';
 import 'ajustes/pantalla_ajustes_emisora_preferida.dart';
@@ -29,6 +31,14 @@ class PantallaAjustes extends StatelessWidget {
     return ListView(
       padding: PluriLayout.pageListPadding,
       children: [
+        // S1 (Tier 1 visual fidelity): the prototype has no global AppBar —
+        // this root now draws its own 56px title row instead of relying on
+        // app.dart's removed shared chrome (which is also where the
+        // sleep-timer action used to live).
+        PluriRootHeader(
+          title: l10n.settingsTitle,
+          onSleepTimer: () => showPluriSleepTimerSheet(context),
+        ),
         PluriScreenHeader(
           title: l10n.settingsTitle,
           subtitle: l10n.settingsSubtitle,

lib/pantallas/pantalla_alarmas.dart

@@ -18,6 +18,8 @@ import '../widgets/pluri_icon.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_premium_widgets.dart';
 import '../widgets/pluri_push_scaffold.dart';
+import '../widgets/pluri_root_header.dart';
+import '../widgets/pluri_sleep_timer_sheet.dart';
 import 'pantalla_vacaciones.dart';
 
 class PantallaAlarmas extends StatelessWidget {
@@ -33,6 +35,14 @@ class PantallaAlarmas extends StatelessWidget {
       child: ListView(
         padding: PluriLayout.pageListPadding,
         children: [
+          // S1 (Tier 1 visual fidelity): the prototype has no global
+          // AppBar — this root now draws its own 56px title row instead of
+          // relying on app.dart's removed shared chrome (which is also
+          // where the sleep-timer action used to live).
+          PluriRootHeader(
+            title: l10n.alarmScreenTitle,
+            onSleepTimer: () => showPluriSleepTimerSheet(context),
+          ),
           PluriScreenHeader(
             title: l10n.alarmScreenTitle,
             subtitle: l10n.alarmScreenSubtitle,

lib/pantallas/pantalla_buscar.dart

@@ -12,6 +12,8 @@ import '../widgets/pluri_icon.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_premium_widgets.dart';
 import '../widgets/pluri_push_scaffold.dart';
+import '../widgets/pluri_root_header.dart';
+import '../widgets/pluri_sleep_timer_sheet.dart';
 import 'package:pluriwave/widgets/tarjeta_emisora.dart';
 
 import 'pantalla_paises.dart';
@@ -140,6 +142,14 @@ class _PantallaBuscarState extends State<PantallaBuscar> {
     return ListView(
       padding: PluriLayout.pageListPadding,
       children: [
+        // S1 (Tier 1 visual fidelity): the prototype has no global AppBar —
+        // this root now draws its own 56px title row instead of relying on
+        // app.dart's removed shared chrome (which is also where the
+        // sleep-timer action used to live).
+        PluriRootHeader(
+          title: l10n.searchScreenTitle,
+          onSleepTimer: () => showPluriSleepTimerSheet(context),
+        ),
         PluriScreenHeader(
           title: l10n.searchScreenTitle,
           subtitle: l10n.searchScreenSubtitle,

lib/pantallas/pantalla_favoritos.dart

@@ -10,6 +10,8 @@ import '../widgets/pluri_icon.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_premium_widgets.dart';
 import '../widgets/pluri_push_scaffold.dart';
+import '../widgets/pluri_root_header.dart';
+import '../widgets/pluri_sleep_timer_sheet.dart';
 import 'package:pluriwave/widgets/tarjeta_emisora.dart';
 import 'ajustes/pantalla_ajustes_emisoras_personalizadas.dart';
 import 'ajustes/pantalla_ajustes_grupos_favoritos.dart';
@@ -113,6 +115,14 @@ class _PantallaFavoritosState extends State<PantallaFavoritos> {
       return ListView(
         padding: PluriLayout.pageListPadding,
         children: [
+          // S1 (Tier 1 visual fidelity): the prototype has no global
+          // AppBar — this root now draws its own 56px title row instead of
+          // relying on app.dart's removed shared chrome (which is also
+          // where the sleep-timer action used to live).
+          PluriRootHeader(
+            title: l10n.favoritesTitle,
+            onSleepTimer: () => showPluriSleepTimerSheet(context),
+          ),
           PluriScreenHeader(
             title: l10n.favoritesTitle,
             subtitle: l10n.favoritesHeaderSubtitle,
@@ -180,6 +190,11 @@ class _PantallaFavoritosState extends State<PantallaFavoritos> {
         child: Column(
           crossAxisAlignment: CrossAxisAlignment.start,
           children: [
+            // S1 (Tier 1 visual fidelity): see the empty-state branch above.
+            PluriRootHeader(
+              title: l10n.favoritesTitle,
+              onSleepTimer: () => showPluriSleepTimerSheet(context),
+            ),
             PluriScreenHeader(
               title: l10n.favoritesTitle,
               subtitle: l10n.favoritesHeaderSubtitle,

lib/pantallas/pantalla_inicio.dart

@@ -14,6 +14,8 @@ import '../tema/pluriwave_theme.dart';
 import '../widgets/pluri_glass_surface.dart';
 import '../widgets/pluri_layout.dart';
 import '../widgets/pluri_premium_widgets.dart';
+import '../widgets/pluri_root_header.dart';
+import '../widgets/pluri_sleep_timer_sheet.dart';
 import '../widgets/visualizador_audio.dart';
 import 'package:pluriwave/widgets/tarjeta_emisora.dart';
 
@@ -39,6 +41,16 @@ class _PantallaInicioState extends State<PantallaInicio> {
 
     return CustomScrollView(
       slivers: [
+        // S1 (Tier 1 visual fidelity): the prototype has no global AppBar —
+        // this root now draws its own 56px title row instead of relying on
+        // app.dart's removed shared chrome (which is also where the
+        // sleep-timer action used to live).
+        SliverToBoxAdapter(
+          child: PluriRootHeader(
+            title: l10n.navHome,
+            onSleepTimer: () => showPluriSleepTimerSheet(context),
+          ),
+        ),
         // WU5 built the hero; WU6 relocated the discovery sections that
         // used to follow it (_seccionCercanas, _seccionTendencias,
         // _chipGeneros, _errorBanner, the browse grid) into
@@ -142,7 +154,6 @@ class _PantallaInicioState extends State<PantallaInicio> {
       ),
     );
   }
-
 }
 
 /// WU5, design ADR-7: the Escuchar embedded player. `EstadoRadio` is the

lib/widgets/pluri_root_header.dart

@@ -0,0 +1,53 @@
+import 'package:flutter/material.dart';
+
+import '../l10n/gen/app_localizations.dart';
+import '../tema/pluriwave_theme.dart';
+
+/// S1 (Tier 1 visual fidelity): the prototype (`t4`) draws no global
+/// `AppBar` — each root paints its own 56px title row inside its own
+/// content instead (e.g. Alarmas `height:56px;padding:0 12px 0 20px`,
+/// Ajustes `height:56px;padding:0 20px`, Explorar `height:56px`). This
+/// widget is that row, reused by all 5 roots so the sleep-timer action
+/// that used to live on `app.dart`'s single shared `AppBar` stays
+/// reachable from every tab.
+class PluriRootHeader extends StatelessWidget {
+  const PluriRootHeader({
+    super.key,
+    required this.title,
+    required this.onSleepTimer,
+  });
+
+  final String title;
+  final VoidCallback onSleepTimer;
+
+  static const double height = 56;
+
+  @override
+  Widget build(BuildContext context) {
+    final type = context.pluriType;
+    final l10n = AppLocalizations.of(context);
+    return SizedBox(
+      height: height,
+      child: Padding(
+        padding: const EdgeInsets.fromLTRB(20, 0, 12, 0),
+        child: Row(
+          children: [
+            Expanded(
+              child: Text(
+                title,
+                maxLines: 1,
+                overflow: TextOverflow.ellipsis,
+                style: type.sectionTitle,
+              ),
+            ),
+            IconButton(
+              icon: const Icon(Icons.bedtime_outlined),
+              tooltip: l10n.sleepTimer,
+              onPressed: onSleepTimer,
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}

lib/widgets/pluri_sleep_timer_sheet.dart

@@ -0,0 +1,253 @@
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+import '../estado/estado_radio.dart';
+import '../l10n/gen/app_localizations.dart';
+import 'pluri_layout.dart';
+
+/// S1 (Tier 1 visual fidelity): extracted from `app.dart`'s old
+/// `_mostrarTimerDialog`, which only the single global `AppBar` could reach.
+/// Now that each root draws its own [PluriRootHeader] instead, this is a
+/// free function any of them can call directly with their own
+/// `BuildContext` — the sleep-timer feature stays reachable from every tab
+/// with no behaviour change.
+void showPluriSleepTimerSheet(BuildContext context) {
+  showModalBottomSheet(
+    context: context,
+    showDragHandle: true,
+    builder:
+        (ctx) => Consumer<EstadoRadio>(
+          builder:
+              (ctx, estado, _) => SafeArea(
+                child: Padding(
+                  padding: PluriLayout.sheetPadding,
+                  child: Column(
+                    mainAxisSize: MainAxisSize.min,
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    children: [
+                      Text(
+                        AppLocalizations.of(ctx).sleepTimer,
+                        style: Theme.of(ctx).textTheme.titleLarge,
+                      ),
+                      const SizedBox(height: PluriLayout.sectionGap),
+                      Text(
+                        AppLocalizations.of(ctx).sleepTimerDescription,
+                        style: Theme.of(ctx).textTheme.bodySmall,
+                      ),
+                      const SizedBox(height: PluriLayout.panelGap),
+                      if (estado.timer.activo)
+                        StreamBuilder<Duration>(
+                          stream: estado.timer.tiempoRestanteStream,
+                          builder: (ctx, snap) {
+                            final restante =
+                                snap.data ?? estado.timer.tiempoRestante;
+                            return Column(
+                              crossAxisAlignment: CrossAxisAlignment.stretch,
+                              children: [
+                                Text(
+                                  _formatearDuracionTimer(
+                                    AppLocalizations.of(ctx),
+                                    restante,
+                                  ),
+                                  style: Theme.of(ctx).textTheme.headlineMedium,
+                                ),
+                                const SizedBox(height: PluriLayout.compactGap),
+                                FilledButton.tonal(
+                                  onPressed: () {
+                                    estado.cancelarTimer();
+                                    Navigator.pop(ctx);
+                                  },
+                                  child: Text(
+                                    AppLocalizations.of(ctx).cancelTimer,
+                                  ),
+                                ),
+                              ],
+                            );
+                          },
+                        )
+                      else
+                        Wrap(
+                          spacing: PluriLayout.compactGap,
+                          runSpacing: PluriLayout.compactGap,
+                          children: [
+                            for (final segundos
+                                in estado.timerSuenoPresetsSegundos)
+                              ActionChip(
+                                label: Text(
+                                  _formatearDuracionTimer(
+                                    AppLocalizations.of(ctx),
+                                    Duration(seconds: segundos),
+                                  ),
+                                ),
+                                onPressed: () {
+                                  estado.iniciarTimerDuracion(
+                                    Duration(seconds: segundos),
+                                  );
+                                  Navigator.pop(ctx);
+                                },
+                              ),
+                            ActionChip(
+                              avatar: const Icon(Icons.tune_rounded, size: 18),
+                              label: Text(AppLocalizations.of(ctx).optionOther),
+                              onPressed: () async {
+                                final duracion =
+                                    await _pedirDuracionPersonalizada(ctx);
+                                if (duracion == null || !ctx.mounted) return;
+                                estado.iniciarTimerDuracion(duracion);
+                                Navigator.pop(ctx);
+                              },
+                            ),
+                          ],
+                        ),
+                    ],
+                  ),
+                ),
+              ),
+        ),
+  );
+}
+
+Future<Duration?> _pedirDuracionPersonalizada(BuildContext context) {
+  return showModalBottomSheet<Duration>(
+    context: context,
+    isScrollControlled: true,
+    showDragHandle: true,
+    builder: (ctx) => const _TimerPersonalizadoSheet(),
+  );
+}
+
+String _formatearDuracionTimer(AppLocalizations l10n, Duration duracion) {
+  final horas = duracion.inHours;
+  final minutos = duracion.inMinutes.remainder(60);
+  final segundos = duracion.inSeconds.remainder(60);
+  if (horas > 0) {
+    return l10n.durationHoursMinutesSeconds(
+      horas,
+      minutos.toString().padLeft(2, '0'),
+      segundos.toString().padLeft(2, '0'),
+    );
+  }
+  if (minutos > 0) {
+    return segundos == 0
+        ? l10n.durationMinutesOnly(minutos)
+        : l10n.durationMinutesSeconds(
+          minutos,
+          segundos.toString().padLeft(2, '0'),
+        );
+  }
+  return l10n.durationSecondsOnly(segundos);
+}
+
+class _TimerPersonalizadoSheet extends StatefulWidget {
+  const _TimerPersonalizadoSheet();
+
+  @override
+  State<_TimerPersonalizadoSheet> createState() =>
+      _TimerPersonalizadoSheetState();
+}
+
+class _TimerPersonalizadoSheetState extends State<_TimerPersonalizadoSheet> {
+  final _horasCtrl = TextEditingController();
+  final _minutosCtrl = TextEditingController(text: '15');
+  final _segundosCtrl = TextEditingController();
+  bool _guardarPreset = true;
+
+  @override
+  void dispose() {
+    _horasCtrl.dispose();
+    _minutosCtrl.dispose();
+    _segundosCtrl.dispose();
+    super.dispose();
+  }
+
+  int _leer(TextEditingController ctrl) => int.tryParse(ctrl.text.trim()) ?? 0;
+
+  Future<void> _confirmar() async {
+    final duracion = Duration(
+      hours: _leer(_horasCtrl),
+      minutes: _leer(_minutosCtrl),
+      seconds: _leer(_segundosCtrl),
+    );
+    if (duracion <= Duration.zero) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text(AppLocalizations.of(context).durationGreaterThanZero),
+        ),
+      );
+      return;
+    }
+    if (_guardarPreset) {
+      await context.read<EstadoRadio>().agregarTimerSuenoPreset(duracion);
+    }
+    if (mounted) Navigator.pop(context, duracion);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final bottom = MediaQuery.viewInsetsOf(context).bottom;
+    return SafeArea(
+      child: Padding(
+        padding: EdgeInsets.fromLTRB(18, 0, 18, 18 + bottom),
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: [
+            Text(
+              AppLocalizations.of(context).customDurationTitle,
+              style: Theme.of(context).textTheme.titleLarge,
+            ),
+            const SizedBox(height: PluriLayout.sectionGap),
+            Row(
+              children: [
+                Expanded(
+                  child: _campoTiempo(
+                    _horasCtrl,
+                    AppLocalizations.of(context).hoursLabel,
+                  ),
+                ),
+                const SizedBox(width: PluriLayout.compactGap),
+                Expanded(
+                  child: _campoTiempo(
+                    _minutosCtrl,
+                    AppLocalizations.of(context).minutesLabel,
+                  ),
+                ),
+                const SizedBox(width: PluriLayout.compactGap),
+                Expanded(
+                  child: _campoTiempo(
+                    _segundosCtrl,
+                    AppLocalizations.of(context).secondsLabel,
+                  ),
+                ),
+              ],
+            ),
+            const SizedBox(height: PluriLayout.compactGap),
+            SwitchListTile.adaptive(
+              contentPadding: EdgeInsets.zero,
+              title: Text(AppLocalizations.of(context).saveQuickAccess),
+              value: _guardarPreset,
+              onChanged: (value) => setState(() => _guardarPreset = value),
+            ),
+            const SizedBox(height: PluriLayout.sectionGap),
+            FilledButton.icon(
+              icon: const Icon(Icons.bedtime_rounded),
+              label: Text(AppLocalizations.of(context).startTimer),
+              onPressed: _confirmar,
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  Widget _campoTiempo(TextEditingController controller, String label) {
+    return TextField(
+      controller: controller,
+      keyboardType: TextInputType.number,
+      decoration: InputDecoration(
+        labelText: label,
+        border: const OutlineInputBorder(),
+      ),
+    );
+  }
+}

test/app_test.dart

@@ -0,0 +1,23 @@
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+
+/// S1 (Tier 1 visual fidelity): the prototype (`t4`) never draws a global
+/// `AppBar` — every root owns its own 56px title row instead (see
+/// `PluriRootHeader` and `root_header_wiring_test.dart`). `app.dart` used to
+/// wrap every tab in `PluriWaveScaffold(appBar: AppBar(...))`; this is a
+/// fast source-level regression guard for that removal, since the widget
+/// under it (`_PaginaPrincipal`) is library-private and constructs real
+/// platform-backed services, so it cannot be safely widget-tested here.
+void main() {
+  test('app.dart no longer constructs a global Material AppBar', () {
+    final source = File('lib/app.dart').readAsStringSync();
+    expect(
+      source.contains('AppBar('),
+      isFalse,
+      reason:
+          'the prototype has no global app bar — each root draws its own '
+          'PluriRootHeader inside its content instead',
+    );
+  });
+}

test/pantallas/root_header_wiring_test.dart

@@ -0,0 +1,208 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pluriwave/estado/estado_alarmas.dart';
+import 'package:pluriwave/estado/estado_busqueda.dart';
+import 'package:pluriwave/estado/estado_ecualizador.dart';
+import 'package:pluriwave/estado/estado_grabacion.dart';
+import 'package:pluriwave/estado/estado_radio.dart';
+import 'package:pluriwave/l10n/gen/app_localizations.dart';
+import 'package:pluriwave/pantallas/pantalla_ajustes.dart';
+import 'package:pluriwave/pantallas/pantalla_alarmas.dart';
+import 'package:pluriwave/pantallas/pantalla_buscar.dart';
+import 'package:pluriwave/pantallas/pantalla_favoritos.dart';
+import 'package:pluriwave/pantallas/pantalla_inicio.dart';
+import 'package:pluriwave/servicios/servicio_alarmas.dart';
+import 'package:pluriwave/widgets/pluri_root_header.dart';
+import 'package:provider/provider.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import '../helpers/fakes.dart';
+import '../helpers/fakes_alarmas.dart';
+
+/// S1 (Tier 1 visual fidelity): `app.dart`'s `PluriWaveScaffold(appBar:
+/// AppBar(...))` is gone — every root now draws its own [PluriRootHeader]
+/// instead, matching the prototype (no screen in `t4` shows a global
+/// `AppBar`). Each root still ALSO carries its pre-existing
+/// `PluriScreenHeader` hero (S2 in this same Tier 1 batch replaces that
+/// separately), so title assertions below are scoped to [PluriRootHeader]'s
+/// own subtree — the title string itself still appears twice on screen
+/// until S2 lands.
+///
+/// Pre-existing project constraint (see `pantalla_ajustes_test.dart`):
+/// PluriGlassSurface paints a background over ListTile's ink layer, which
+/// Flutter flags as a warning-level assertion, not a correctness bug.
+void _suppressListTileInkAssertion() {
+  final original = FlutterError.onError;
+  FlutterError.onError = (details) {
+    if (details.exceptionAsString().contains(
+      'ListTile background color or ink splashes may be invisible',
+    )) {
+      return;
+    }
+    original?.call(details);
+  };
+  addTearDown(() => FlutterError.onError = original);
+}
+
+void main() {
+  setUp(() {
+    SharedPreferences.setMockInitialValues({});
+  });
+
+  Future<File> archivoCustomVacio() async => File(
+    '${Directory.current.path}/test/fixtures/emisoras_custom_vacio.json',
+  );
+
+  EstadoRadio crearEstadoRadio() => EstadoRadio(
+    audio: FakeServicioAudio(),
+    favoritos: FakeServicioFavoritos(),
+    radio: FakeServicioRadio(),
+    servicioEcualizador: FakeServicioEcualizador(),
+    servicioGrabacion: FakeServicioGrabacionRadioInactiva(),
+    resolverArchivoCustom: archivoCustomVacio,
+    iniciarAutomaticamente: false,
+  );
+
+  Widget testApp(EstadoRadio estado, Widget body, {EstadoAlarmas? alarmas}) {
+    return MultiProvider(
+      providers: [
+        ChangeNotifierProvider<EstadoRadio>.value(value: estado),
+        ListenableProvider<EstadoEcualizador>.value(value: estado.ecualizador),
+        ListenableProvider<EstadoGrabacion>.value(value: estado.grabacion),
+        ListenableProvider<EstadoBusqueda>.value(value: estado.busqueda),
+        if (alarmas != null)
+          ChangeNotifierProvider<EstadoAlarmas>.value(value: alarmas),
+      ],
+      child: MaterialApp(
+        locale: const Locale('en'),
+        localizationsDelegates: AppLocalizations.localizationsDelegates,
+        supportedLocales: AppLocalizations.supportedLocales,
+        home: Scaffold(body: body),
+      ),
+    );
+  }
+
+  void setLargeSurface(WidgetTester tester) {
+    tester.view.physicalSize = const Size(1440, 3200);
+    tester.view.devicePixelRatio = 1.0;
+    addTearDown(tester.view.resetPhysicalSize);
+    addTearDown(tester.view.resetDevicePixelRatio);
+  }
+
+  Future<void> pumpStable(WidgetTester tester) async {
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 100));
+  }
+
+  Finder titleInHeader(String title) => find.descendant(
+    of: find.byType(PluriRootHeader),
+    matching: find.text(title),
+  );
+
+  testWidgets(
+    'Escuchar draws its own PluriRootHeader with the tab title, no AppBar',
+    (tester) async {
+      _suppressListTileInkAssertion();
+      setLargeSurface(tester);
+      final estado = crearEstadoRadio();
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(testApp(estado, const PantallaInicio()));
+      await pumpStable(tester);
+
+      expect(find.byType(PluriRootHeader), findsOneWidget);
+      expect(titleInHeader('Listen'), findsOneWidget);
+      expect(find.byType(AppBar), findsNothing);
+    },
+  );
+
+  testWidgets(
+    'Buscar draws its own PluriRootHeader with the search title, no AppBar',
+    (tester) async {
+      _suppressListTileInkAssertion();
+      setLargeSurface(tester);
+      final estado = crearEstadoRadio();
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(testApp(estado, const PantallaBuscar()));
+      await pumpStable(tester);
+
+      expect(find.byType(PluriRootHeader), findsOneWidget);
+      expect(titleInHeader('Search signal'), findsOneWidget);
+      expect(find.byType(AppBar), findsNothing);
+    },
+  );
+
+  testWidgets(
+    'Favoritos (empty state) draws its own PluriRootHeader, no AppBar',
+    (tester) async {
+      _suppressListTileInkAssertion();
+      setLargeSurface(tester);
+      final estado = crearEstadoRadio();
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(testApp(estado, const PantallaFavoritos()));
+      await pumpStable(tester);
+
+      expect(find.byType(PluriRootHeader), findsOneWidget);
+      expect(titleInHeader('Favorites'), findsOneWidget);
+      expect(find.byType(AppBar), findsNothing);
+    },
+  );
+
+  testWidgets('Alarmas draws its own PluriRootHeader, no AppBar', (
+    tester,
+  ) async {
+    _suppressListTileInkAssertion();
+    setLargeSurface(tester);
+    final estado = crearEstadoRadio();
+    final alarmas = EstadoAlarmas(
+      servicio: ServicioAlarmas(reloj: () => DateTime(2026, 6, 1, 6, 0)),
+      android: FakePuertoAlarmasAndroid(),
+      iniciarAutomaticamente: false,
+    );
+    addTearDown(estado.dispose);
+    addTearDown(alarmas.dispose);
+
+    await tester.pumpWidget(
+      testApp(estado, const PantallaAlarmas(), alarmas: alarmas),
+    );
+    await pumpStable(tester);
+
+    expect(find.byType(PluriRootHeader), findsOneWidget);
+    expect(titleInHeader('Music wake-up'), findsOneWidget);
+    expect(find.byType(AppBar), findsNothing);
+  });
+
+  testWidgets(
+    'Ajustes draws its own PluriRootHeader, no AppBar, and its bedtime '
+    'action opens the sleep-timer sheet',
+    (tester) async {
+      _suppressListTileInkAssertion();
+      setLargeSurface(tester);
+      final estado = crearEstadoRadio();
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(testApp(estado, const PantallaAjustes()));
+      await pumpStable(tester);
+
+      expect(find.byType(PluriRootHeader), findsOneWidget);
+      expect(titleInHeader('Settings'), findsOneWidget);
+      expect(find.byType(AppBar), findsNothing);
+
+      await tester.tap(find.byIcon(Icons.bedtime_outlined));
+      await pumpStable(tester);
+
+      // Not `find.text('Sleep timer')` — Ajustes' own "Sleep timer"
+      // FilaAjuste row (`l10n.timerSectionTitle`) coincidentally shares the
+      // exact same string as `l10n.sleepTimer`. The description line is
+      // unique to the sheet this action opens.
+      expect(
+        find.text('Smooth radio shutdown with an exact countdown.'),
+        findsOneWidget,
+      );
+    },
+  );
+}

test/widgets/pluri_root_header_test.dart

@@ -0,0 +1,58 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pluriwave/l10n/gen/app_localizations.dart';
+import 'package:pluriwave/tema/pluriwave_theme.dart';
+import 'package:pluriwave/widgets/pluri_root_header.dart';
+
+/// S1 (Tier 1 visual fidelity): the prototype draws no global `AppBar` —
+/// each root instead owns a plain 56px title row inside its own content
+/// (`t4`, e.g. Alarmas line 325 `height:56px`, Ajustes line 511, Explorar
+/// line 641). [PluriRootHeader] is that row, shared by all 5 roots so the
+/// sleep-timer action that used to live on `app.dart`'s single global
+/// `AppBar` stays reachable from every tab.
+void main() {
+  Widget host(Widget child) {
+    return MaterialApp(
+      theme: PluriWaveTheme.dark(),
+      locale: const Locale('en'),
+      localizationsDelegates: AppLocalizations.localizationsDelegates,
+      supportedLocales: AppLocalizations.supportedLocales,
+      home: Scaffold(body: child),
+    );
+  }
+
+  testWidgets('renders the given title and is exactly 56px tall', (
+    tester,
+  ) async {
+    await tester.pumpWidget(
+      host(PluriRootHeader(title: 'Settings', onSleepTimer: () {})),
+    );
+
+    expect(find.text('Settings'), findsOneWidget);
+    expect(PluriRootHeader.height, 56);
+    final size = tester.getSize(find.byType(PluriRootHeader));
+    expect(size.height, 56);
+  });
+
+  testWidgets('exposes a bedtime action that invokes onSleepTimer when '
+      'tapped', (tester) async {
+    var tapped = false;
+    await tester.pumpWidget(
+      host(PluriRootHeader(title: 'Alarms', onSleepTimer: () => tapped = true)),
+    );
+
+    expect(find.byIcon(Icons.bedtime_outlined), findsOneWidget);
+    await tester.tap(find.byIcon(Icons.bedtime_outlined));
+    await tester.pump();
+
+    expect(tapped, isTrue);
+  });
+
+  testWidgets('never builds a Material AppBar', (tester) async {
+    await tester.pumpWidget(
+      host(PluriRootHeader(title: 'Search signal', onSleepTimer: () {})),
+    );
+
+    expect(find.byType(AppBar), findsNothing);
+  });
+}