Patch Changes

• #396 76284f0 Thanks @whoiskatrin! - Add backup and restore API for directory snapshots.

  createBackup() archives a directory as a compressed squashfs image and uploads it to R2. restoreBackup() downloads and mounts the archive with copy-on-write semantics via FUSE overlay.

  Requires R2 presigned URL credentials: set R2_ACCESS_KEY_ID, R2_SECRET_ACCESS_KEY, CLOUDFLARE_ACCOUNT_ID, and BACKUP_BUCKET_NAME as environment variables alongside the BACKUP_BUCKET R2 binding. Archives transfer directly between the container and R2 at ~24 MB/s upload / ~93 MB/s download.

• #403 bbfc579 Thanks @whoiskatrin! - Add proxyToOpencodeServer() to proxy requests directly to a running OpenCode server without web UI redirect behavior. Use this helper for headless API and CLI traffic where raw request forwarding is preferred.