feat(tokens): add design tokens, type scale, push scaffold, and root nav state

test/widget_test.dart

@@ -3,7 +3,12 @@
 // existe en este proyecto — corregido para usar PluriWaveApp.
 // Los tests de integración completos (audio, streaming) requieren un dispositivo.
 
+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_bottom_navigation.dart';
+import 'package:pluriwave/widgets/pluri_icon.dart';
 
 void main() {
   testWidgets('Placeholder — tests de integración requieren dispositivo', (
@@ -14,4 +19,54 @@ void main() {
     // por el test de smoke incorrecto del boilerplate original.
     expect(true, isTrue);
   });
+
+  // Spec app-navigation-shell — "Escuchar Tab Rename Preserves the ARB Key"
+  // and "Escuchar uses the home glyph": the former "Inicio" tab is
+  // relabeled by changing navHome's VALUE only; PluriIconGlyph.home stays
+  // its icon. app.dart's real _navItems()/_paginas wiring is private to
+  // that library, so this pins the same two contracts at the pieces it
+  // composes: the ARB value, the PluriNavItem the tab is built from, and
+  // that PluriIconGlyph.home still resolves to a renderable icon.
+  group('Escuchar tab rename (WU1)', () {
+    test('navHome value renamed in en/es without touching the key', () async {
+      final l10nEs = await AppLocalizations.delegate.load(const Locale('es'));
+      final l10nEn = await AppLocalizations.delegate.load(const Locale('en'));
+
+      expect(l10nEs.navHome, 'Escuchar');
+      expect(l10nEn.navHome, 'Listen');
+    });
+
+    test(
+      'the home tab item still pairs navHome with PluriIconGlyph.home',
+      () async {
+        final l10n = await AppLocalizations.delegate.load(const Locale('es'));
+
+        final item = PluriNavItem(
+          glyph: PluriIconGlyph.home,
+          label: l10n.navHome,
+        );
+
+        expect(item.label, 'Escuchar');
+        expect(item.glyph, PluriIconGlyph.home);
+      },
+    );
+
+    testWidgets('PluriIconGlyph.home still renders as the home icon', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: PluriWaveTheme.dark(),
+          home: const Scaffold(
+            body: PluriIcon(
+              glyph: PluriIconGlyph.home,
+              semanticLabel: 'Escuchar',
+            ),
+          ),
+        ),
+      );
+
+      expect(find.bySemanticsLabel('Escuchar'), findsOneWidget);
+    });
+  });
 }