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/core/api/api_client.dart

@@ -1,3 +1,4 @@
+import 'dart:convert';
 import 'package:dio/dio.dart';
 import 'api_exception.dart';
 import 'api_interceptor.dart';
@@ -92,4 +93,30 @@ class ApiClient implements IApiClient {
       throw ApiException.fromDioError(e);
     }
   }
+
+  @override
+  Future<Stream<String>> getSseLines(
+    String path, {
+    Map<String, String>? headers,
+  }) async {
+    try {
+      final response = await _dio.get<ResponseBody>(
+        path,
+        options: Options(
+          responseType: ResponseType.stream,
+          headers: headers,
+        ),
+      );
+      final responseBody = response.data;
+      if (responseBody == null) {
+        return const Stream<String>.empty();
+      }
+      return responseBody.stream
+          .cast<List<int>>()
+          .transform(utf8.decoder)
+          .transform(const LineSplitter());
+    } on DioException catch (e) {
+      throw ApiException.fromDioError(e);
+    }
+  }
 }

apps/lib/core/api/i_api_client.dart

@@ -5,4 +5,8 @@ abstract class IApiClient {
   Future<Response<T>> post<T>(String path, {dynamic data, Options? options});
   Future<Response<T>> patch<T>(String path, {dynamic data, Options? options});
   Future<Response<T>> delete<T>(String path, {dynamic data, Options? options});
+  Future<Stream<String>> getSseLines(
+    String path, {
+    Map<String, String>? headers,
+  });
 }

apps/lib/core/api/mock_api_client.dart

@@ -1,18 +1,58 @@
 import 'package:dio/dio.dart';
 import 'i_api_client.dart';
 
-typedef MockHandler = dynamic Function(dynamic data);
+class MockRequest {
+  final String path;
+  final String method;
+  final dynamic data;
+  final Options? options;
+  final Map<String, String>? headers;
+
+  MockRequest({
+    required this.path,
+    required this.method,
+    this.data,
+    this.options,
+    this.headers,
+  });
+}
+
+typedef MockHandler = dynamic Function(MockRequest request);
+
+class _PatternRoute {
+  final RegExp pattern;
+  final String method;
+  final MockHandler handler;
+
+  _PatternRoute({
+    required this.pattern,
+    required this.method,
+    required this.handler,
+  });
+}
 
 class MockApiClient implements IApiClient {
   final Map<String, MockHandler> _handlers = {};
+  final List<_PatternRoute> _patternHandlers = [];
 
   void registerHandler(String path, String method, MockHandler handler) {
     final key = '$path:$method';
     _handlers[key] = handler;
   }
 
+  void registerPatternHandler(RegExp pattern, String method, MockHandler handler) {
+    _patternHandlers.add(
+      _PatternRoute(
+        pattern: pattern,
+        method: method.toUpperCase(),
+        handler: handler,
+      ),
+    );
+  }
+
   void clearMocks() {
     _handlers.clear();
+    _patternHandlers.clear();
   }
 
   @override
@@ -47,6 +87,54 @@ class MockApiClient implements IApiClient {
     return _handleRequest('DELETE', path, data: data, options: options);
   }
 
+  @override
+  Future<Stream<String>> getSseLines(
+    String path, {
+    Map<String, String>? headers,
+  }) async {
+    final key = '$path:SSE';
+    final direct = _handlers[key];
+    if (direct != null) {
+      final response = direct(
+        MockRequest(
+          path: path,
+          method: 'SSE',
+          headers: headers,
+        ),
+      );
+      if (response is Stream<String>) {
+        return response;
+      }
+      if (response is Iterable<String>) {
+        return Stream<String>.fromIterable(response);
+      }
+      return const Stream<String>.empty();
+    }
+    for (final route in _patternHandlers) {
+      if (route.method != 'SSE') {
+        continue;
+      }
+      if (!route.pattern.hasMatch(path)) {
+        continue;
+      }
+      final response = route.handler(
+        MockRequest(
+          path: path,
+          method: 'SSE',
+          headers: headers,
+        ),
+      );
+      if (response is Stream<String>) {
+        return response;
+      }
+      if (response is Iterable<String>) {
+        return Stream<String>.fromIterable(response);
+      }
+      return const Stream<String>.empty();
+    }
+    return const Stream<String>.empty();
+  }
+
   Future<Response<T>> _handleRequest<T>(
     String method,
     String path, {
@@ -55,11 +143,17 @@ class MockApiClient implements IApiClient {
   }) async {
     await Future.delayed(const Duration(milliseconds: 200));
 
-    final key = '$path:$method';
-    final handler = _handlers[key];
+    final handler = _resolveHandler(path: path, method: method);
 
     if (handler != null) {
-      final response = handler(data);
+      final response = handler(
+        MockRequest(
+          path: path,
+          method: method,
+          data: data,
+          options: options,
+        ),
+      );
       if (response is Response) {
         return response as Response<T>;
       }
@@ -76,4 +170,21 @@ class MockApiClient implements IApiClient {
       requestOptions: RequestOptions(path: path),
     );
   }
+
+  MockHandler? _resolveHandler({required String path, required String method}) {
+    final key = '$path:$method';
+    final direct = _handlers[key];
+    if (direct != null) {
+      return direct;
+    }
+    for (final route in _patternHandlers) {
+      if (route.method != method.toUpperCase()) {
+        continue;
+      }
+      if (route.pattern.hasMatch(path)) {
+        return route.handler;
+      }
+    }
+    return null;
+  }
 }