Twitter (syndication + auth GraphQL) mapped every non-2xx to NotFound,
killing retries on 429/5xx; bsky never checked status; pixiv network
errors arrived wrapped in PixivError and were excluded from the retry
loop. New FetchError::Transient covers 429/5xx from all sites, the
retry loop now also retries Pixiv errors, and 404/410 stay permanent.
download_to_temp now uses download_media_limited: non-photos abort the
moment the 10 MiB upload cap is crossed mid-stream (no more full-body
buffering before the size check), photos cap at the 512 MiB decode
budget, and the ugoira frame zip gets a 512 MiB cap. MediaTooLarge
routes to the existing smaller-URL fallback.
Sniff the frame extension from magic bytes instead of the entry filename,
cap each frame at 64 MiB (declared size + streamed read), and map a
panicked encode worker to the existing degrade path instead of
expect()-panicking the whole fetch handler.
bsky video embeds expose only an m3u8 playlist, which Telegram cannot
fetch. Download the master/variant playlists and TS segments through the
shared client (proxy-aware, size-capped), then concat-remux locally;
keep the temp dir alive via Fetched._keep_alive like the ugoira path.
Also adds site::download_media_limited (streaming size cap), status
checks on media_size, and moves the ffmpeg probe to site/mod.rs for
pixiv/bsky to share.
Apply rustfmt to the 11 files that had drifted (86 hunks): x-media
site modules (bsky/pixiv/twitter) and xmedia-bot (config/main/
photo/send). Formatting only - no semantic changes; full test suite
still green.