RustFS returns empty bodies for ranged GETs whose start offset is past
~5.9 MB on single-file proxy MP4s. HEAD reports correct size, full GET
(`bytes=0-`) works, but `bytes=8179166-` comes back 206 + correct
Content-Range header with zero bytes. Confirmed via direct S3 probe
against broadcastmgmt.cloud/dragonmam (see scratch tests).
Workaround in mam-api `GET /api/v1/assets/:id/video` until the proxy
worker emits HLS (planned v1.2.1):
- HEAD the object first to learn total size (also gives ETag /
Last-Modified for conditional requests).
- No-Range / unparseable-Range / pre-EOF requests \u2192 plain pipe.
- Parsed `bytes=N-M` requests below RUSTFS_RANGE_SAFE_START
(default 5_500_000) \u2192 direct ranged GET, RustFS handles fine.
- Anything reaching into the broken zone \u2192 stream from offset 0,
drop bytes below start, stop at end. Memory stays flat; extra
bandwidth = (end+1 - requested-size) per seek.
- Genuinely out-of-range \u2192 416 with Cache-Control: no-store so the
browser doesn't poison its cache.
Also stashes (not yet wired up) the HLS pieces we'll need for the
follow-up: `segmentToHls` ffmpeg helper + `uploadDirectoryToS3`
worker s3 helper. Harmless additions; not referenced by any code path
yet.
Confirmed against the affected asset (a72aaa03-...): bytes=0-100k +
50% +100k native pass-through; 70% +100k and near-EOF previously hung
the browser, now stream correctly via the stitched path.
Refs #143.
