feat(engine): 添加MCP连接管理和工具集成功能

- 集成MCP连接管理器，支持MCP服务器连接
- 添加多种内置工具：ClarifyTool、CronTool、DelegateTool、ExecuteCodeTool、
  PatchFileTool、ProcessTool、SendMessageTool、SpawnTool、TerminalTool、
  TodoTool、WebFetchTool、WebSearchTool、WriteFileTool等
- 实现工具注册和装配功能
- 添加技能选择上下文参数
- 支持思考模式控制参数thinking_enabled

feat(coordinator): 重构任务执行计划器参数命名

- 将learning_candidate_enabled重命名为allow_candidate_generation
- 更新TeamGraphScheduler中的参数传递
- 修改LocalAgentRunner中的相关参数处理
- 更新README文档中的相应描述

refactor(context): 标准化工具调用参数格式

- 添加_json导入用于参数序列化
- 实现_provider_tool_calls方法标准化OpenAI兼容的工具调用载荷
- 修复工具调用中参数非字符串类型的序列化问题

refactor(session): 优化消息历史记录过滤逻辑

- 修改get_messages_as_conversation为基于运行状态过滤消息
- 排除未完成、失败或错误结束的运行记录
- 改进对话历史的可见性控制机制

fix(store): 修复FTS索引重建逻辑

- 添加异常处理防止FTS索引创建失败
- 实现_rebuild_fts_index方法重新构建全文搜索索引
- 优化索引触发器和表的维护流程

app-instance/backend/tests/unit/test_main_agent_router.py

@@ -0,0 +1,116 @@
+from __future__ import annotations
+
+import asyncio
+
+from beaver.engine.providers.base import LLMProvider, LLMResponse
+from beaver.tasks import MainAgentRouter, TaskRecord
+
+
+class RouterProvider(LLMProvider):
+    def __init__(self, response: str | Exception) -> None:
+        super().__init__()
+        self.response = response
+        self.calls: list[dict] = []
+
+    async def chat(
+        self,
+        messages: list[dict],
+        tools: list[dict] | None = None,
+        model: str | None = None,
+        max_tokens: int = 4096,
+        temperature: float = 0.7,
+        thinking_enabled: bool | None = None,
+    ) -> LLMResponse:
+        self.calls.append(
+            {
+                "max_tokens": max_tokens,
+                "temperature": temperature,
+                "model": model,
+                "thinking_enabled": thinking_enabled,
+            }
+        )
+        if isinstance(self.response, Exception):
+            raise self.response
+        return LLMResponse(content=self.response, finish_reason="stop", provider_name="stub", model="stub-model")
+
+    def get_default_model(self) -> str:
+        return "stub-model"
+
+
+def _task() -> TaskRecord:
+    return TaskRecord(
+        task_id="task-1",
+        session_id="web:task",
+        description="实现任务连续性",
+        goal="实现任务连续性",
+        constraints=[],
+        priority=0,
+        status="awaiting_feedback",
+        creator="test",
+        created_at="now",
+        updated_at="now",
+        metadata={"short_title": "任务连续性"},
+    )
+
+
+def test_router_continues_active_task_from_llm_decision() -> None:
+    provider = RouterProvider('{"action":"continue_task","reason":"related","short_title":"任务连续性"}')
+    decision = asyncio.run(
+        MainAgentRouter().classify(
+            "再把输入框标识也补上",
+            active_task=_task(),
+            provider=provider,
+        )
+    )
+
+    assert decision.is_task
+    assert decision.starts_new_task is False
+    assert decision.short_title == "任务连续性"
+    assert provider.calls[0]["max_tokens"] == 256
+
+
+def test_router_receives_thinking_mode() -> None:
+    provider = RouterProvider('{"action":"simple_chat","reason":"simple"}')
+    decision = asyncio.run(
+        MainAgentRouter().classify(
+            "你好",
+            provider=provider,
+            thinking_enabled=False,
+        )
+    )
+
+    assert not decision.is_task
+    assert provider.calls[0]["thinking_enabled"] is False
+
+
+def test_router_closes_active_task_from_llm_decision() -> None:
+    decision = asyncio.run(
+        MainAgentRouter().classify(
+            "这个任务结束了",
+            active_task=_task(),
+            provider=RouterProvider('{"action":"close_task","reason":"user said done"}'),
+        )
+    )
+
+    assert not decision.is_task
+    assert decision.closes_task is True
+
+
+def test_router_fallback_keeps_active_task_but_not_new_task() -> None:
+    active = asyncio.run(
+        MainAgentRouter().classify(
+            "继续",
+            active_task=_task(),
+            provider=RouterProvider(RuntimeError("provider down")),
+        )
+    )
+    inactive = asyncio.run(
+        MainAgentRouter().classify(
+            "implement something",
+            active_task=None,
+            provider=RouterProvider(RuntimeError("provider down")),
+        )
+    )
+
+    assert active.is_task
+    assert not inactive.is_task