feat: AG-UI 协议对齐与路由导航功能

- 前端: 添加 SSE 流式支持、stateSnapshot 事件、路由导航工具
- 前端: 实现工具调用审批流程，支持 pending 状态展示
- 后端: Agent 状态管理与会话持久化相关重构
- 文档: 新增 agent-agui-full-alignance 设计文档
- 测试: 补充相关单元测试和集成测试

apps/lib/features/chat/data/tools/tool_registry.dart

@@ -1,8 +1,11 @@
+import 'route_navigation_tool.dart';
+
 typedef ToolHandler =
     Future<Map<String, dynamic>> Function(Map<String, dynamic> args);
 
 /// 工具常量
 const _toolNameCreateCalendar = 'create_calendar_event';
+const _toolNameNavigateRoute = 'navigate_to_route';
 const _defaultTimezone = 'Asia/Shanghai';
 const _defaultEventColor = '#4F46E5';
 const _defaultSourceType = 'agentGenerated';
@@ -62,6 +65,20 @@ class ToolRegistry {
       handler: _handleCreateCalendarEvent,
     );
 
+    _tools[_toolNameNavigateRoute] = ToolDefinition(
+      name: _toolNameNavigateRoute,
+      description: '在前端执行路由跳转',
+      parameters: {
+        'type': 'object',
+        'properties': {
+          'target': {'type': 'string', 'description': '跳转目标路由'},
+          'replace': {'type': 'boolean', 'description': '是否 replace 导航'},
+        },
+        'required': ['target'],
+      },
+      handler: _handleNavigateRoute,
+    );
+
     _initialized = true;
   }
 
@@ -84,6 +101,12 @@ class ToolRegistry {
     };
   }
 
+  static Future<Map<String, dynamic>> _handleNavigateRoute(
+    Map<String, dynamic> args,
+  ) async {
+    return RouteNavigationTool.instance.execute(args);
+  }
+
   static ToolDefinition? getTool(String name) => _tools[name];
   static List<ToolDefinition> getAllTools() => _tools.values.toList();