Compose: upload picked files to /media with progress, thumbnails via the
auth-scoped serve route, per-attachment alt text, remove, ≤4 cap with the
Mastodon norm hint, in-flight blocking. Video drawer: Producer section —
lower-third editor, logo key field, MediaRecorder voiceover (record/
stop/review/re-take/upload), produce submission with lane + label, job
progress, derived-asset link. Local types for both contracts.
