feat: implement channel runtime connectors

.env.example

@@ -28,3 +28,19 @@ BEAVER_OUTLOOK_MCP_SERVER_ID=outlook_mcp
 
 # Must be reachable from auth-portal and authz-service containers.
 BEAVER_DEPLOY_URL=http://beaver-deploy-control:8090
+
+# External connector sidecar
+EXTERNAL_CONNECTOR_TOKEN=
+BEAVER_BRIDGE_TOKEN=
+BEAVER_BRIDGE_BASE_URL=http://app-instance:8080
+EXTERNAL_CONNECTOR_PORT=8787
+CONNECTOR_PUBLIC_BASE_URL=http://localhost:8787
+# fake | vendor_cli | weixin_ilink
+CONNECTOR_PROVIDER=vendor_cli
+CONNECTOR_COMMAND_TIMEOUT_SECONDS=120
+WEIXIN_CONNECT_COMMAND=
+WEIXIN_STATUS_COMMAND=
+WEIXIN_SEND_COMMAND=
+FEISHU_CONNECT_COMMAND=
+FEISHU_STATUS_COMMAND=
+FEISHU_SEND_COMMAND=