feat: 增强 HomeScreen 录音交互与 ChatBloc 状态管理

- 新增录音启动延迟处理，解决权限未就绪时的竞态问题
- 实现历史分页滚动位置保持，提升加载体验
- 添加文本输入框点击键盘显示与焦点管理
- 优化 ChatBloc provider 到 MultiBlocProvider 支持
- 修复 ApiException 429 错误详情解析（支持 JSON 字符串 body）
- 改进 LocalNotificationService 精确闹钟权限请求
- 优化 UiSchemaRenderer GridView children 生成
- 支持导航 action 的 replace 参数
- 移除 Agent router 速率限制逻辑（_allow_run_request, _allow_transcribe_request）
- 补充相关单元测试与集成测试

apps/test/features/chat/ui_schema_renderer_test.dart

@@ -130,7 +130,9 @@ void main() {
       expect(find.textContaining('无效 UI Schema'), findsOneWidget);
     });
 
-    testWidgets('handles navigation action and jumps by path', (tester) async {
+    testWidgets('handles navigation action by pushing target page', (
+      tester,
+    ) async {
       final schema = {
         'version': '2.0',
         'root': {
@@ -174,6 +176,60 @@ void main() {
       await tester.pumpAndSettle();
 
       expect(find.text('todo detail 123 from assistant'), findsOneWidget);
+      expect(router.canPop(), isTrue);
+
+      router.pop();
+      await tester.pumpAndSettle();
+
+      expect(find.text('查看待办'), findsOneWidget);
+    });
+
+    testWidgets('uses replace navigation when replace is true', (tester) async {
+      final schema = {
+        'version': '2.0',
+        'root': {
+          'type': 'stack',
+          'direction': 'vertical',
+          'appearance': 'plain',
+          'children': [
+            {
+              'type': 'button',
+              'label': '替换跳转',
+              'style': 'primary',
+              'action': {
+                'type': 'navigation',
+                'path': '/todo/456',
+                'replace': true,
+              },
+            },
+          ],
+        },
+      };
+
+      final router = GoRouter(
+        initialLocation: '/',
+        routes: [
+          GoRoute(
+            path: '/',
+            builder: (context, state) =>
+                Scaffold(body: UiSchemaRenderer.renderSchema(schema)),
+          ),
+          GoRoute(
+            path: '/todo/:id',
+            builder: (context, state) =>
+                Text('todo detail ${state.pathParameters['id']}'),
+          ),
+        ],
+      );
+
+      await tester.pumpWidget(MaterialApp.router(routerConfig: router));
+      await tester.tap(find.text('替换跳转'));
+      await tester.pumpAndSettle();
+
+      expect(find.text('todo detail 456'), findsOneWidget);
+      expect(router.canPop(), isFalse);
+
+      expect(find.text('todo detail 456'), findsOneWidget);
     });
 
     testWidgets('does not navigate for placeholder path', (tester) async {