TRUNCATE-everything ResetDB before every test forces a commit fsync; the CI DB is rebuilt each run so durability buys nothing. ALTER SYSTEM via docker exec (the services: block can't override the postgres command line). Non-fatal so a perms surprise degrades to slow, never red.
Per the playbook the operator shared from another project (~17x speedup observed there). Measure before/after in the next two CI runs.
Closes Scribe #614, #615, server half of #616 surfaced by the 2026-06-04 divergent-provider audit.
- streamURL helper now used everywhere /api/tracks/{id}/stream is built (was inline concat in playlists.go and cast_token.go); add streamURLWithExt for the .ext cast variant.
- audioContentType in media.go is the canonical file_format -> MIME lookup; mimeForFormat in cast_token.go is now a thin wrapper that overrides the unknown-format fallback to audio/mpeg (Sonos rejects octet-stream). Adds mpeg/vorbis/wave aliases. Subsonic's contentTypeForFormat stays frozen per docs.
- coverart.ResolveAlbumPath extracted; api and subsonic both delegate to it.
bvandeusen