Fix config.json permission denied on HF Spaces persistent storage
luckfun233
534def0
On HuggingFace Spaces, the persistent /data volume may retain files owned by root or a different UID after container rebuilds, causing permission denied when ds2api tries to save config changes.
Two-layer fix:
- entrypoint.sh: always chown+chmod config files on startup, not just when creating them for the first time
- Go writeConfigBytes: atomic write (temp file + rename) with fallback that removes the old file and retries if permission denied
