gravenhollow RustFS is already S3-compatible — expose it through
the existing Cloudflare Tunnel with a dedicated HTTPRoute at
assets.daviestechlabs.io. Cloudflare CDN caches at edge PoPs.
Eliminates: R2 bucket, rclone sync CronJob, R2 API token, and
6-hour sync delay. Single source of truth on gravenhollow.
