Re-add the deploy job dropped during open-source cleanup. The job pulls
the just-built image and restarts the compose stack in vars.DEPLOY_PATH.
The gate `if: vars.DEPLOY_PATH != ''` keeps the workflow safe for
public mirroring: no path appears in the YAML, and any fork without
DEPLOY_PATH set will silently skip the deploy step.
zhengchen.tao
2b595ea27b