feat(ci): add migration rollback and remove duplicate chown in Jenkinsfile

- Save pre-deploy SHA before git pull for automatic rollback
- On migrate failure: git reset + migrate:rollback + reinstall deps + restart
- Remove duplicate chown from Restart Services stage (already in Fix Permissions)
- Clean up .deploy_prev_sha after deploy completes

.gitignore

@@ -1,5 +1,6 @@
 .env
 deploy.sh
+.deploy_prev_sha
 /node_modules
 /vendor
 /sourcefiles