Adds ReleaseRepository/ReleaseManager (IReleaseService) for paged medium-filtered
release reads and Session/Mix satellite writes, UnifiedReleaseService orchestrating
vault+SQL, and ReleaseController (5 endpoints). Refactors WaveformProfileService for
configurable bucketCount/vaultName (backward-compatible) and adds the mix-waveforms vault.
Promotes brittle error-string literals to named constants (MixHasNoTrackMessage,
MixTrackNoAudioMessage) on UnifiedReleaseService.
daniel-c-harvey
ca44fc8794