feat(j0.3): socle transverse (Result/Failure, theme, router, DI)

- core/error : Result<S> maison (Ok/Err) + Failure scellee avec egalite de valeur
- core/theme : AppTheme Material 3 (palette coucher, cibles tactiles enfant)
- core/router : routes nommees child/parentGate/parent (Navigator 1, placeholders)
- core/di : conventions providers
- CLAUDE.md §7 : Result maison & Navigator 1 actes (YAGNI)
- ROADMAP : 0.3 cochee, Jalon 0 termine
- corrections code review : egalite Failure, assertions tests, Map.unmodifiable

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/core/result_test.dart

@@ -0,0 +1,82 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:storytime/core/error/failure.dart';
+import 'package:storytime/core/error/result.dart';
+
+void main() {
+  group('Result', () {
+    const failure = UnexpectedFailure('boom');
+
+    group('Ok', () {
+      test('map transforme la valeur', () {
+        const result = Ok<int>(1);
+        expect(result.map((v) => v + 1), equals(const Ok<int>(2)));
+      });
+
+      test('map préserve le type Ok et produit la bonne valeur', () {
+        const result = Ok<String>('hello');
+        final mapped = result.map((v) => v.length);
+        expect(mapped, isA<Ok<int>>());
+        expect((mapped as Ok<int>).value, equals(5));
+      });
+
+      test('fold appelle la branche ok', () {
+        const result = Ok<int>(42);
+        final out = result.fold(onOk: (v) => 'ok:$v', onErr: (_) => 'err');
+        expect(out, equals('ok:42'));
+      });
+
+      test('when appelle la branche ok et pas la branche err', () {
+        const result = Ok<int>(7);
+        var okCalled = false;
+        var errCalled = false;
+        result.when(ok: (_) => okCalled = true, err: (_) => errCalled = true);
+        expect(okCalled, isTrue);
+        expect(errCalled, isFalse);
+      });
+    });
+
+    group('Err', () {
+      test('map ne transforme pas — reste Err avec le même Failure', () {
+        const result = Err<int>(failure);
+        final mapped = result.map((v) => v + 1);
+        expect(mapped, isA<Err<int>>());
+        expect((mapped as Err<int>).failure, same(failure));
+      });
+
+      test('fold appelle la branche err', () {
+        const result = Err<int>(failure);
+        final out = result.fold(
+          onOk: (_) => 'ok',
+          onErr: (f) => 'err:${f.message}',
+        );
+        expect(out, equals('err:boom'));
+      });
+
+      test('when appelle la branche err et pas la branche ok', () {
+        const result = Err<int>(failure);
+        var okCalled = false;
+        var errCalled = false;
+        result.when(ok: (_) => okCalled = true, err: (_) => errCalled = true);
+        expect(errCalled, isTrue);
+        expect(okCalled, isFalse);
+      });
+    });
+
+    group('Failure sous-types', () {
+      test('NetworkFailure expose le message', () {
+        const f = NetworkFailure('timeout');
+        expect(f.message, equals('timeout'));
+      });
+
+      test('NotFoundFailure expose le message', () {
+        const f = NotFoundFailure('episode 42');
+        expect(f.message, equals('episode 42'));
+      });
+
+      test('UnexpectedFailure expose le message', () {
+        const f = UnexpectedFailure('oops');
+        expect(f.message, equals('oops'));
+      });
+    });
+  });
+}

test/core/theme_test.dart

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+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:storytime/core/theme/app_theme.dart';
+
+void main() {
+  group('AppTheme', () {
+    testWidgets('useMaterial3 est activé', (tester) async {
+      await tester.pumpWidget(
+        MaterialApp(theme: AppTheme.light(), home: const SizedBox.shrink()),
+      );
+
+      final theme = Theme.of(tester.element(find.byType(SizedBox)));
+      expect(theme.useMaterial3, isTrue);
+    });
+
+    testWidgets('la couleur primaire correspond à la palette coucher', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        MaterialApp(theme: AppTheme.light(), home: const SizedBox.shrink()),
+      );
+
+      final theme = Theme.of(tester.element(find.byType(SizedBox)));
+      // Palette « coucher » : violet/indigo doux.
+      // On vérifie que la teinte de seed est bien dans le spectre attendu.
+      final primary = theme.colorScheme.primary;
+      // HSL : le bleu/violet doit dominer sur le rouge et le vert.
+      final hsl = HSLColor.fromColor(primary);
+      expect(
+        hsl.hue,
+        inInclusiveRange(200.0, 320.0),
+        reason: 'La couleur primaire doit être dans le spectre bleu-violet',
+      );
+    });
+
+    test('AppTheme.light() retourne un ThemeData non nul', () {
+      expect(AppTheme.light(), isA<ThemeData>());
+    });
+  });
+}