feat(worker): adopt canonical public URL

README.md

@@ -185,7 +185,7 @@ used in a trusted disposable environment.
 | `RSMON_TOKEN` | yes | none | Worker bearer token. |
 | `WORKER_HOST` | no | `0.0.0.0` | Operator-console bind address. |
 | `WORKER_PORT` | no | `27401` | Operator-console port. |
-| `WORKER_URL` | no | none | Public URL advertised to the control plane. |
+| `PUBLIC_URL` | no | none | Advertised public origin (scheme + host, no path). Canonical name; the legacy `WORKER_URL` is still read during the bounded migration in `docs/public-endpoint-and-identity.md`. |
 | `WORKER_LOGIN` | yes | none | Operator-console basic-auth login. |
 | `WORKER_PASSWORD` | yes | none | Operator-console basic-auth password. |
 | `RSMON_WEBAPP_DATA_DIR` | no | user data directory | SQLite and local UI state. |