fix: enforce strict config validation

extensions/zalo/index.ts

@@ -1,4 +1,5 @@
 import type { ClawdbotPluginApi } from "clawdbot/plugin-sdk";
+import { emptyPluginConfigSchema } from "clawdbot/plugin-sdk";
 
 import { zaloDock, zaloPlugin } from "./src/channel.js";
 import { handleZaloWebhookRequest } from "./src/monitor.js";
@@ -8,6 +9,7 @@ const plugin = {
   id: "zalo",
   name: "Zalo",
   description: "Zalo channel plugin (Bot API)",
+  configSchema: emptyPluginConfigSchema(),
   register(api: ClawdbotPluginApi) {
     setZaloRuntime(api.runtime);
     api.registerChannel({ plugin: zaloPlugin, dock: zaloDock });