Background-job transcode (ffmpeg/libopus) after source store; pure C# Ogg
walker builds the 0.5s-bucketed granule→byte seek index + captures the
OpusHead/OpusTags setup header into a per-track sidecar in a new track-opus
vault. Best-effort, additive, regenerated on replace-audio.
ILoudnessAlgorithm strategy (RmsLoudnessAlgorithm first impl), WaveformProfileService
stores quantized byte[] sidecar in new MediaFileVault (profiles vault), wired into
UnifiedTrackService.UploadAsync; failure is logged and swallowed. WaveformProfileDto
and WaveformProfileOptions in shared projects.