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/services/__init__.py

@@ -1,6 +1,15 @@
 """Application services for Beaver."""
 
-from .agent_service import AgentService
-from .memory_service import MemoryService
-
 __all__ = ["AgentService", "MemoryService"]
+
+
+def __getattr__(name: str):
+    if name == "AgentService":
+        from .agent_service import AgentService
+
+        return AgentService
+    if name == "MemoryService":
+        from .memory_service import MemoryService
+
+        return MemoryService
+    raise AttributeError(name)

app-instance/backend/beaver/services/agent_service.py

@@ -17,6 +17,7 @@ from pathlib import Path
 from typing import Any
 
 from beaver.engine import AgentLoop, AgentProfile, AgentRunResult, EngineLoader
+from beaver.foundation.events import InboundMessage, OutboundMessage
 
 
 class AgentService:
@@ -36,11 +37,12 @@ class AgentService:
         self,
         *,
         workspace: str | Path | None = None,
+        config_path: str | Path | None = None,
         profile: AgentProfile | None = None,
         loader: EngineLoader | None = None,
     ) -> None:
         self.profile = profile or AgentProfile()
-        self.loader = loader or EngineLoader(workspace=workspace)
+        self.loader = loader or EngineLoader(workspace=workspace, config_path=config_path)
         self._loop: AgentLoop | None = None
         self._run_task: asyncio.Task[None] | None = None
 
@@ -189,6 +191,60 @@ class AgentService:
         loop = self.create_loop()
         return await loop.submit_direct(message, **kwargs)
 
+    async def handle_inbound_message(self, inbound: InboundMessage) -> OutboundMessage:
+        """把 bus inbound 映射成标准 runtime 调用，并返回结构化 outbound。"""
+
+        try:
+            result = await self.submit_direct(
+                inbound.content,
+                session_id=inbound.session_id,
+                source=f"gateway:{inbound.channel}",
+                user_id=inbound.user_id,
+                title=inbound.title,
+                execution_context=inbound.execution_context,
+                model=inbound.model,
+                provider_name=inbound.provider_name,
+                embedding_model=inbound.embedding_model,
+            )
+        except Exception as exc:
+            return self.build_outbound_error(inbound, detail=str(exc))
+        return self.build_outbound_message(inbound, result)
+
+    @staticmethod
+    def build_outbound_message(inbound: InboundMessage, result: AgentRunResult) -> OutboundMessage:
+        """把一次 runtime 正常结果转成 bus outbound。"""
+
+        return OutboundMessage(
+            message_id=inbound.message_id,
+            channel=inbound.channel,
+            session_id=result.session_id,
+            run_id=result.run_id,
+            content=result.output_text,
+            finish_reason=result.finish_reason,
+            provider_name=result.provider_name,
+            model=result.model,
+            usage=dict(result.usage),
+            metadata={"inbound_metadata": dict(inbound.metadata)},
+        )
+
+    @staticmethod
+    def build_outbound_error(
+        inbound: InboundMessage,
+        *,
+        detail: str,
+        finish_reason: str = "error",
+    ) -> OutboundMessage:
+        """把 inbound 处理失败转换成结构化 outbound 错误消息。"""
+
+        return OutboundMessage(
+            message_id=inbound.message_id,
+            channel=inbound.channel,
+            session_id=inbound.session_id,
+            content=detail,
+            finish_reason=finish_reason,
+            metadata={"error": detail, "inbound_metadata": dict(inbound.metadata)},
+        )
+
     def run_direct(
         self,
         message: str,