libSceCustomMusicAudioOut technical debt

sceCustomMusicAudioOutFinalize, sceCustomMusicAudioOutGetAllMusicVolume, sceCustomMusicAudioOutGetMuted, sceCustomMusicAudioOutGetVolume and sceCustomMusicAudioOutSetAllMusicVolume (libSceCustomMusicAudioOut) - names and NIDs are present in the PS5 3.20 export inventory, but no credible prototypes were found. The declarations have no parameters solely to resolve known imports; this is not an ABI claim and callers must not call them until signatures are verified
sceCustomMusicAudioOutGetLastOutputTime, sceCustomMusicAudioOutInitialize, sceCustomMusicAudioOutOutput, sceCustomMusicAudioOutSetMuted, sceCustomMusicAudioOutSetVolume throw through NotImplemented_nid_no_patch. Names and NIDs are bound by the 13.60 firmware inventory; signatures and behaviour remain unknown. Parameterless int declarations are import-resolution placeholders, not confirmed ABI signatures. Their service behaviour is unimplemented.