Docs: cover heartbeat, cron, and plugin route updates

docs/tools/plugin.md

@@ -62,7 +62,7 @@ Schema instead. See [Plugin manifest](/plugins/manifest).
 Plugins can register:
 
 - Gateway RPC methods
-- Gateway HTTP handlers
+- Gateway HTTP routes
 - Agent tools
 - CLI commands
 - Background services
@@ -106,6 +106,37 @@ Notes:
 - Uses core media-understanding audio configuration (`tools.media.audio`) and provider fallback order.
 - Returns `{ text: undefined }` when no transcription output is produced (for example skipped/unsupported input).
 
+## Gateway HTTP routes
+
+Plugins can expose HTTP endpoints with `api.registerHttpRoute(...)`.
+
+```ts
+api.registerHttpRoute({
+  path: "/acme/webhook",
+  auth: "plugin",
+  match: "exact",
+  handler: async (_req, res) => {
+    res.statusCode = 200;
+    res.end("ok");
+    return true;
+  },
+});
+```
+
+Route fields:
+
+- `path`: route path under the gateway HTTP server.
+- `auth`: required. Use `"gateway"` to require normal gateway auth, or `"plugin"` for plugin-managed auth/webhook verification.
+- `match`: optional. `"exact"` (default) or `"prefix"`.
+- `replaceExisting`: optional. Allows the same plugin to replace its own existing route registration.
+- `handler`: return `true` when the route handled the request.
+
+Notes:
+
+- `api.registerHttpHandler(...)` is obsolete. Use `api.registerHttpRoute(...)`.
+- Plugin routes must declare `auth` explicitly.
+- Exact `path + match` conflicts are rejected unless `replaceExisting: true`, and one plugin cannot replace another plugin's route.
+
 ## Plugin SDK import paths
 
 Use SDK subpaths instead of the monolithic `openclaw/plugin-sdk` import when