```

feat(agent): 添加对持久化子智能体的支持并增强委派管理

添加了持久化子智能体的完整生命周期管理功能，包括创建、更新、删除和查询API接口。
新增了子智能体的JSON-RPC通信协议支持，实现了远程调用和任务管理功能。

同时增强了委派管理器的功能：
- 添加了对本地委派、插件委派和本地回退的开关控制
- 实现了持久化子智能体任务的自动检测和本地执行保护
- 增加了对不同委派类型的权限验证机制

修改了智能体注册表以支持插件智能体的条件性包含，并更新了工具注册逻辑以支持可选工具。

BREAKING CHANGE: 委派管理器的构造函数签名已更改，添加了新的控制参数。
```

app-instance/backend/nanobot/agent/loop.py

@@ -76,6 +76,13 @@ class AgentLoop:
         channels_config: ChannelsConfig | None = None,
         authz_config: Any | None = None,
         backend_identity: Any | None = None,
+        allow_spawn: bool = True,
+        allow_message: bool = True,
+        allow_cron: bool = True,
+        include_local_fallback: bool = True,
+        allow_local_delegation: bool = True,
+        allow_plugin_delegation: bool = True,
+        include_plugin_agents: bool = True,
     ):
         from nanobot.config.schema import A2AConfig, ExecToolConfig
         # 基础依赖与运行参数。
@@ -95,6 +102,13 @@ class AgentLoop:
         self.restrict_to_workspace = restrict_to_workspace
         self.authz_config = authz_config
         self.backend_identity = backend_identity
+        self.allow_spawn = allow_spawn
+        self.allow_message = allow_message
+        self.allow_cron = allow_cron
+        self.include_local_fallback = include_local_fallback
+        self.allow_local_delegation = allow_local_delegation
+        self.allow_plugin_delegation = allow_plugin_delegation
+        self.include_plugin_agents = include_plugin_agents
 
         # 核心组件：上下文构建、会话管理、工具注册、子代理管理。
         self.plugins = PluginLoader(workspace)
@@ -106,6 +120,8 @@ class AgentLoop:
             skills=self.skills,
             allow_skill_cards=self.a2a_config.allow_skill_cards,
             allow_workspace_agents=self.a2a_config.allow_workspace_agents,
+            include_local_fallback=self.include_local_fallback,
+            include_plugin_agents=self.include_plugin_agents,
         )
         self.context = ContextBuilder(
             workspace,
@@ -137,6 +153,9 @@ class AgentLoop:
             allowed_hosts=self.a2a_config.allowed_hosts,
             authz_config=self.authz_config,
             backend_identity=self.backend_identity,
+            allow_local_delegation=self.allow_local_delegation,
+            allow_plugin_delegation=self.allow_plugin_delegation,
+            allow_local_fallback=self.include_local_fallback,
         )
 
         # 运行时状态位。
@@ -193,11 +212,13 @@ class AgentLoop:
         # 网络、消息、子代理工具按职责注册。
         self.tools.register(WebSearchTool(api_key=self.brave_api_key))
         self.tools.register(WebFetchTool())
-        self.tools.register(MessageTool(send_callback=self.bus.publish_outbound))
-        self.tools.register(SpawnTool(manager=self.delegation))
+        if self.allow_message:
+            self.tools.register(MessageTool(send_callback=self.bus.publish_outbound))
+        if self.allow_spawn:
+            self.tools.register(SpawnTool(manager=self.delegation))
 
         # 只有注入 cron_service 时才暴露 cron 工具，避免空引用。
-        if self.cron_service:
+        if self.cron_service and self.allow_cron:
             self.tools.register(CronTool(self.cron_service))
 
     async def _connect_mcp(self) -> None: