fix(timer): show the live countdown in the sleep timer sheet

showPluriSleepTimerSheet already had a working countdown branch
(ServicioTimer.tiempoRestanteStream), but every preset and the custom
duration flow popped the sheet immediately after starting the timer --
so the countdown never rendered in the primary flow, only if the user
happened to reopen the sheet afterwards.

Stop popping the sheet on start; the existing Consumer<EstadoRadio>
already reacts to iniciarTimerDuracion's notifyListeners and swaps to
the countdown view live. Also make the sheet scroll-controlled: at a
realistic phone width the countdown's title + description + headline-
sized remaining-time text overflowed the default half-screen cap that
never mattered while the sheet always closed before that view could
render.

lib/widgets/pluri_sleep_timer_sheet.dart

@@ -14,6 +14,13 @@ import 'pluri_layout.dart';
 void showPluriSleepTimerSheet(BuildContext context) {
   showModalBottomSheet(
     context: context,
+    // Issue 2 (feedback-pruebas): without this, the sheet is capped to a
+    // FRACTION of the screen height. That never mattered while the sheet
+    // always closed immediately after picking a duration (see the removed
+    // `Navigator.pop` calls below) -- now that the countdown view actually
+    // stays open, its title + description + headline-sized remaining-time
+    // text can overflow that capped height on a real phone width.
+    isScrollControlled: true,
     showDragHandle: true,
     builder:
         (ctx) => Consumer<EstadoRadio>(
@@ -79,12 +86,17 @@ void showPluriSleepTimerSheet(BuildContext context) {
                                     Duration(seconds: segundos),
                                   ),
                                 ),
-                                onPressed: () {
+                                // Issue 2 (feedback-pruebas): no longer pops
-                                  estado.iniciarTimerDuracion(
+                                // the sheet -- `estado.iniciarTimerDuracion`
-                                    Duration(seconds: segundos),
+                                // notifies this `Consumer<EstadoRadio>`,
-                                  );
+                                // which swaps straight to the countdown
-                                  Navigator.pop(ctx);
+                                // view above so the user actually SEES the
-                                },
+                                // remaining time instead of the sheet just
+                                // closing with no feedback.
+                                onPressed:
+                                    () => estado.iniciarTimerDuracion(
+                                      Duration(seconds: segundos),
+                                    ),
                               ),
                             ActionChip(
                               avatar: const Icon(Icons.tune_rounded, size: 18),
@@ -93,8 +105,9 @@ void showPluriSleepTimerSheet(BuildContext context) {
                                 final duracion =
                                     await _pedirDuracionPersonalizada(ctx);
                                 if (duracion == null || !ctx.mounted) return;
+                                // Issue 2: same as above -- stays open on
+                                // the countdown view rather than closing.
                                 estado.iniciarTimerDuracion(duracion);
-                                Navigator.pop(ctx);
                               },
                             ),
                           ],

test/widgets/pluri_sleep_timer_sheet_test.dart

@@ -0,0 +1,184 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pluriwave/estado/estado_radio.dart';
+import 'package:pluriwave/l10n/gen/app_localizations.dart';
+import 'package:pluriwave/widgets/pluri_sleep_timer_sheet.dart';
+import 'package:provider/provider.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import '../helpers/fakes.dart';
+import '../helpers/fakes_alarmas.dart';
+
+/// Issue 2 (feedback-pruebas): "Timer de sueño" opened from Escuchar (and
+/// every other root header) showed a bottom sheet with no visible
+/// countdown. `ServicioTimer.tiempoRestanteStream`/`tiempoRestante` already
+/// existed and this sheet already had a `StreamBuilder` countdown branch —
+/// but every preset/custom-duration action popped the sheet immediately
+/// after starting the timer, so the countdown never had a chance to render
+/// in the primary flow. Zero test coverage existed for this file before.
+EstadoRadio _estado() => EstadoRadio(
+  audio: FakeServicioAudio(),
+  favoritos: FakeServicioFavoritos(),
+  radio: FakeServicioRadio(),
+  servicioEcualizador: FakeServicioEcualizador(),
+  servicioGrabacion: FakeServicioGrabacionRadioInactiva(),
+  iniciarAutomaticamente: false,
+);
+
+Widget _host(EstadoRadio estado) {
+  return ChangeNotifierProvider<EstadoRadio>.value(
+    value: estado,
+    child: MaterialApp(
+      locale: const Locale('es'),
+      localizationsDelegates: AppLocalizations.localizationsDelegates,
+      supportedLocales: AppLocalizations.supportedLocales,
+      home: Scaffold(
+        body: Builder(
+          builder:
+              (context) => TextButton(
+                onPressed: () => showPluriSleepTimerSheet(context),
+                child: const Text('abrir'),
+              ),
+        ),
+      ),
+    ),
+  );
+}
+
+void main() {
+  setUp(() {
+    SharedPreferences.setMockInitialValues({});
+  });
+
+  // The default 800x600 test viewport is shorter than a typical phone —
+  // same fix `pantalla_reproductor_test.dart`/`pantalla_inicio_test.dart`
+  // already established for other bottom-sheet/full-bleed content.
+  void ajustarSuperficieRealista(WidgetTester tester) {
+    tester.view.physicalSize = const Size(390, 844);
+    tester.view.devicePixelRatio = 1.0;
+    addTearDown(tester.view.resetPhysicalSize);
+    addTearDown(tester.view.resetDevicePixelRatio);
+  }
+
+  testWidgets(
+    'selecting a preset keeps the sheet open and switches it to the live '
+    'remaining-time countdown, instead of closing with no feedback',
+    (tester) async {
+      ajustarSuperficieRealista(tester);
+      final estado = _estado();
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(_host(estado));
+      await tester.tap(find.text('abrir'));
+      await tester.pumpAndSettle();
+
+      final l10n = AppLocalizations.of(tester.element(find.text('abrir')));
+
+      expect(estado.timer.activo, isFalse);
+      expect(find.byType(ActionChip), findsWidgets);
+
+      final chip = tester.widget<ActionChip>(
+        find.widgetWithText(ActionChip, l10n.durationMinutesOnly(5)),
+      );
+      chip.onPressed!();
+      await tester.pump();
+
+      expect(estado.timer.activo, isTrue);
+      expect(
+        find.byType(ActionChip),
+        findsNothing,
+        reason: 'issue 2: the picker is replaced by the countdown view',
+      );
+      expect(find.text(l10n.cancelTimer), findsOneWidget);
+      expect(
+        find.text(l10n.durationMinutesOnly(5)),
+        findsOneWidget,
+        reason: 'issue 2: the remaining time is now surfaced live',
+      );
+
+      // `ServicioTimer` starts a REAL periodic Timer -- `addTearDown`
+      // callbacks run too late to satisfy the "no pending timers" check
+      // (a well-known flutter_test ordering quirk), so it must be
+      // cancelled here, inside the test body, before it ends.
+      await estado.timer.cancelar();
+    },
+  );
+
+  testWidgets('reopening the sheet while a timer is already active shows the '
+      'countdown immediately, not the duration picker', (tester) async {
+    ajustarSuperficieRealista(tester);
+    final estado = _estado();
+    addTearDown(estado.dispose);
+    estado.iniciarTimerDuracion(const Duration(minutes: 10));
+
+    await tester.pumpWidget(_host(estado));
+    await tester.tap(find.text('abrir'));
+    await tester.pumpAndSettle();
+
+    final l10n = AppLocalizations.of(tester.element(find.text('abrir')));
+    expect(find.byType(ActionChip), findsNothing);
+    expect(find.text(l10n.cancelTimer), findsOneWidget);
+    expect(find.text(l10n.durationMinutesOnly(10)), findsOneWidget);
+
+    // See the comment in the previous test — cancel before the body ends.
+    await estado.timer.cancelar();
+  });
+
+  testWidgets(
+    'cancelling from the countdown view stops the timer and closes the '
+    'sheet',
+    (tester) async {
+      ajustarSuperficieRealista(tester);
+      final estado = _estado();
+      addTearDown(estado.dispose);
+      estado.iniciarTimerDuracion(const Duration(minutes: 10));
+
+      await tester.pumpWidget(_host(estado));
+      await tester.tap(find.text('abrir'));
+      await tester.pumpAndSettle();
+
+      final l10n = AppLocalizations.of(tester.element(find.text('abrir')));
+      final boton = tester.widget<FilledButton>(
+        find.widgetWithText(FilledButton, l10n.cancelTimer),
+      );
+      boton.onPressed!();
+      await tester.pumpAndSettle();
+
+      expect(estado.timer.activo, isFalse);
+      expect(find.text(l10n.cancelTimer), findsNothing);
+    },
+  );
+
+  testWidgets(
+    'starting a custom duration ALSO keeps the sheet open on the countdown '
+    'view, not just the presets',
+    (tester) async {
+      ajustarSuperficieRealista(tester);
+      final estado = _estado();
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(_host(estado));
+      await tester.tap(find.text('abrir'));
+      await tester.pumpAndSettle();
+
+      final l10n = AppLocalizations.of(tester.element(find.text('abrir')));
+      await tester.tap(find.text(l10n.optionOther));
+      await tester.pumpAndSettle();
+
+      // Confirm the custom-duration sub-sheet directly (default prefilled
+      // value is already "15" minutes -- see _TimerPersonalizadoSheetState).
+      final confirmar = tester.widget<FilledButton>(
+        find.widgetWithText(FilledButton, l10n.startTimer),
+      );
+      confirmar.onPressed!();
+      await tester.pumpAndSettle();
+
+      expect(estado.timer.activo, isTrue);
+      expect(find.byType(ActionChip), findsNothing);
+      expect(find.text(l10n.cancelTimer), findsOneWidget);
+
+      // See the comment in the first test — cancel before the body ends.
+      await estado.timer.cancelar();
+    },
+  );
+}