fix(paises): eyebrows outside the card, country count, header search

Audit 5.4 (t4:254/260): "Tus idiomas" and "Todos" eyebrows now sit
OUTSIDE any card at title-tier (20px) padding, styled with
eyebrowLabel -- were titleMedium w900 inside a PluriGlassSurface.
"Todos" also gains its missing total count ("{title} · {count}").

Audit 5.7 (t4:252): the header gained a real `search` action -- toggles
an inline TextField that filters the country list by name or ISO
code, not a decorative no-op button. New ARB key countriesSearchHint.

Item 5.6 (station count as a subtitle line, not a trailing widget) was
already fixed as an undocumented side effect of Tier3's row rebuild
(3303bd3) -- reconfirmed by direct read, no change needed here.

test/pantallas/pantalla_paises_test.dart

@@ -4,6 +4,7 @@ import 'package:pluriwave/estado/estado_busqueda.dart';
 import 'package:pluriwave/l10n/gen/app_localizations.dart';
 import 'package:pluriwave/modelos/pais_radio.dart';
 import 'package:pluriwave/pantallas/pantalla_paises.dart';
+import 'package:pluriwave/widgets/pluri_glass_surface.dart';
 import 'package:pluriwave/widgets/pluri_push_scaffold.dart';
 import 'package:provider/provider.dart';
 
@@ -62,7 +63,9 @@ void main() {
         tester.element(find.byType(PantallaPaises)),
       );
       expect(find.text(l10n.countriesYourLanguagesTitle), findsOneWidget);
-      expect(find.text(l10n.countriesAllTitle), findsOneWidget);
+      // Audit 5.4: "Todos" now carries the total count as part of the
+      // same eyebrow string ("{title} · {count}"), not a bare title.
+      expect(find.textContaining(l10n.countriesAllTitle), findsOneWidget);
 
       // Full alphabetical list: all 3 fetched countries render.
       expect(find.text('Argentina'), findsOneWidget);
@@ -201,6 +204,66 @@ void main() {
     );
   });
 
+  group('visual fidelity (audit 5.4/5.7)', () {
+    testWidgets(
+      'the section eyebrows sit OUTSIDE any card, styled as an eyebrow '
+      'label, and "Todos" carries the total country count (t4:254/260)',
+      (tester) async {
+        final estado = EstadoBusqueda(
+          radio: FakeServicioRadio(
+            paises: const [
+              PaisRadio(nombre: 'Spain', codigoIso: 'ES', numeroEmisoras: 482),
+              PaisRadio(
+                nombre: 'Argentina',
+                codigoIso: 'AR',
+                numeroEmisoras: 120,
+              ),
+              PaisRadio(nombre: 'France', codigoIso: 'FR', numeroEmisoras: 75),
+            ],
+          ),
+        );
+        addTearDown(estado.dispose);
+
+        await tester.pumpWidget(buildScreen(estado));
+        await pumpEstable(tester);
+
+        final l10n = AppLocalizations.of(
+          tester.element(find.byType(PantallaPaises)),
+        );
+
+        final eyebrow = tester.widget<Text>(
+          find.text(l10n.countriesYourLanguagesTitle),
+        );
+        expect(eyebrow.style?.fontSize, 11);
+        expect(eyebrow.style?.fontWeight, FontWeight.w800);
+
+        expect(
+          find.ancestor(
+            of: find.text(l10n.countriesYourLanguagesTitle),
+            matching: find.byType(PluriGlassSurface),
+          ),
+          findsNothing,
+          reason: 'the eyebrow must not be a descendant of any card',
+        );
+
+        expect(
+          find.textContaining('${l10n.countriesAllTitle} · 3'),
+          findsOneWidget,
+        );
+      },
+    );
+
+    testWidgets('the header carries a search action (t4:252)', (tester) async {
+      final estado = EstadoBusqueda(radio: FakeServicioRadio(paises: const []));
+      addTearDown(estado.dispose);
+
+      await tester.pumpWidget(buildScreen(estado));
+      await pumpEstable(tester);
+
+      expect(find.byIcon(Icons.search_rounded), findsOneWidget);
+    });
+  });
+
   testWidgets(
     'cargarPaises no se re-dispara si ya hay datos en caché al reconstruir',
     (tester) async {