feat(app-instance): 集成Beaver后端并更新配置管理

集成新的Beaver后端服务到应用实例中，替换原有的nanobot实现。

主要变更包括：
- 在Dockerfile和环境配置中添加Beaver相关路径和配置变量
- 更新工作目录结构从.nanobot到.beaver
- 实现Beaver引擎加载器，支持配置文件加载和工具组装
- 添加内置工具如ListDirectoryTool、ReadFileTool、SearchFilesTool
- 更新消息处理流程，支持通道适配器和网关模式
- 重构技能系统，支持显式工具提示和嵌入式检索
- 改进错误处理和生命周期管理

此变更使应用实例能够使用统一的Beaver后端进行AI代理运行时管理。

app-instance/backend/beaver/interfaces/web/app.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from collections.abc import AsyncIterator, Callable
-from contextlib import asynccontextmanager
+from contextlib import asynccontextmanager, suppress
 from pathlib import Path
 from types import SimpleNamespace
 from typing import Any
@@ -56,6 +56,7 @@ async def _app_lifespan(
     app: FastAPI,
     *,
     workspace: str | Path | None,
+    config_path: str | Path | None,
     service: AgentService | None,
     manage_service_lifecycle: bool | None,
     shutdown_timeout_seconds: float | None,
@@ -63,7 +64,7 @@ async def _app_lifespan(
 ) -> AsyncIterator[None]:
     """把 Web app 接到 AgentService lifecycle 上。"""
 
-    attached_service = service or AgentService(workspace=workspace)
+    attached_service = service or AgentService(workspace=workspace, config_path=config_path)
     owns_service = manage_service_lifecycle if manage_service_lifecycle is not None else service is None
     app.state.agent_service = attached_service
     started = False
@@ -71,8 +72,15 @@ async def _app_lifespan(
         try:
             await attached_service.start()
             started = True
-        except Exception:
-            attached_service.close()
+        except BaseException:
+            with suppress(BaseException):
+                if attached_service.is_running:
+                    await attached_service.shutdown(
+                        timeout_seconds=shutdown_timeout_seconds,
+                        force=shutdown_force,
+                    )
+                else:
+                    attached_service.close()
             raise
     try:
         yield
@@ -87,6 +95,7 @@ async def _app_lifespan(
 def create_app(
     *,
     workspace: str | Path | None = None,
+    config_path: str | Path | None = None,
     service: AgentService | None = None,
     manage_service_lifecycle: bool | None = None,
     shutdown_timeout_seconds: float | None = 5.0,
@@ -106,6 +115,7 @@ def create_app(
         lifespan=lambda fastapi_app: _app_lifespan(
             fastapi_app,
             workspace=workspace,
+            config_path=config_path,
             service=service,
             manage_service_lifecycle=manage_service_lifecycle,
             shutdown_timeout_seconds=shutdown_timeout_seconds,