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/test/features/chat/chat_bloc_test.dart

@@ -211,5 +211,35 @@ void main() {
         ),
       ],
     );
+
+    blocTest<ChatBloc, ChatState>(
+      'toolCallResult without ui removes pending tool call and does not add empty card',
+      build: () => chatBloc,
+      seed: () => ChatState(
+        items: [
+          ToolCallItem(
+            id: 'tc_1',
+            callId: 'tc_1',
+            toolName: 'navigate_to_route',
+            args: {'target': '/calendar/dayweek', '__nonce': 'nonce_1'},
+            status: ToolCallStatus.executing,
+            timestamp: DateTime.now(),
+            sender: MessageSender.ai,
+          ),
+        ],
+      ),
+      act: (bloc) {
+        service.onEvent(
+          ToolCallResultEvent(
+            messageId: 'msg_tool_1',
+            toolCallId: 'tc_1',
+            content: '{"result":{"ok":true}}',
+          ),
+        );
+      },
+      expect: () => [
+        isA<ChatState>().having((s) => s.items.isEmpty, 'items empty', true),
+      ],
+    );
   });
 }