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/create-instance.sh

@@ -194,7 +194,7 @@ if outlook_mcp_url:
 data = {
     "agents": {
         "defaults": {
-            "workspace": "/root/.nanobot/workspace",
+            "workspace": "/root/.beaver/workspace",
             "model": os.environ["MODEL"],
         }
     },
@@ -505,13 +505,13 @@ PY
 fi
 
 INSTANCE_ROOT="${INSTANCES_ROOT}/${INSTANCE_SLUG}"
-NANOBOT_HOME="${INSTANCE_ROOT}/nanobot-home"
-CONFIG_PATH="${NANOBOT_HOME}/config.json"
-AUTH_USERS_PATH="${NANOBOT_HOME}/web_auth_users.json"
-RUNTIME_ENV_PATH="${NANOBOT_HOME}/runtime.env"
-WORKSPACE_PATH="${NANOBOT_HOME}/workspace"
+BEAVER_HOME="${INSTANCE_ROOT}/beaver-home"
+CONFIG_PATH="${BEAVER_HOME}/config.json"
+AUTH_USERS_PATH="${BEAVER_HOME}/web_auth_users.json"
+RUNTIME_ENV_PATH="${BEAVER_HOME}/runtime.env"
+WORKSPACE_PATH="${BEAVER_HOME}/workspace"
 
-mkdir -p "$NANOBOT_HOME" "$WORKSPACE_PATH"
+mkdir -p "$BEAVER_HOME" "$WORKSPACE_PATH"
 
 render_config_json "$CONFIG_PATH"
 render_auth_users_json "$AUTH_USERS_PATH"
@@ -540,8 +540,12 @@ RUN_ARGS=(
   --name "$CONTAINER_NAME"
   --restart unless-stopped
   -p "${HOST_BIND_IP}:${HOST_PORT}:8080"
-  -v "${NANOBOT_HOME}:/root/.nanobot"
-  -e "NANOBOT_AUTH_FILE=/root/.nanobot/web_auth_users.json"
+  -v "${BEAVER_HOME}:/root/.beaver"
+  -e "BEAVER_HOME=/root/.beaver"
+  -e "BEAVER_CONFIG_PATH=/root/.beaver/config.json"
+  -e "BEAVER_WORKSPACE=/root/.beaver/workspace"
+  -e "NANOBOT_HOME=/root/.beaver"
+  -e "NANOBOT_AUTH_FILE=/root/.beaver/web_auth_users.json"
   -e "NANOBOT_FRONTEND_PUBLIC_BASE_URL=${PUBLIC_URL}"
   -e "APP_PUBLIC_PORT=8080"
   -e "APP_FRONTEND_PORT=3000"
@@ -567,7 +571,7 @@ docker run "${RUN_ARGS[@]}" "$IMAGE_NAME" >/dev/null
   --host-port "$HOST_PORT" \
   --public-url "$PUBLIC_URL" \
   --instance-root "$INSTANCE_ROOT" \
-  --nanobot-home "$NANOBOT_HOME" \
+  --nanobot-home "$BEAVER_HOME" \
   --config-path "$CONFIG_PATH" \
   --auth-users-path "$AUTH_USERS_PATH" \
   --network-name "$NETWORK_NAME" \
@@ -589,7 +593,8 @@ image_name=${IMAGE_NAME}
 host_port=${HOST_PORT}
 public_url=${PUBLIC_URL}
 instance_root=${INSTANCE_ROOT}
-nanobot_home=${NANOBOT_HOME}
+beaver_home=${BEAVER_HOME}
+nanobot_home=${BEAVER_HOME}
 config_path=${CONFIG_PATH}
 auth_users_path=${AUTH_USERS_PATH}
 runtime_env_path=${RUNTIME_ENV_PATH}