Feishu: validate webhook signatures before parsing (#55083)

* Feishu: validate webhook signatures before parsing

* Scripts: allow Feishu raw body guard callsite

extensions/feishu/runtime-api.ts

@@ -2,3 +2,8 @@
 // Keep this barrel thin and aligned with the local extension surface.
 
 export * from "openclaw/plugin-sdk/feishu";
+export {
+  isRequestBodyLimitError,
+  readRequestBodyWithLimit,
+  requestBodyErrorToText,
+} from "openclaw/plugin-sdk/webhook-ingress";