The git user inside the gitea container couldn't write to the NAS-mounted
/tmp/backup directory. Now dumps to /tmp first, then uses docker cp to
extract the file to the sidecar's backup directory.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Alpine sidecar container runs gitea dump via docker exec at 2 AM daily,
writing backups to /data/backup/gitea/ with 7-day retention.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>