libSceAudiodec.native technical debt

libSceAudiodec.native pending exports - 14 named callable exports are listed in the PS5 3.20 export table and were cross-checked against the same module in PS5 firmware 13.60. Their signatures and behaviour are unverified; the declarations use the no-parameter unknown-signature convention and throw through NotImplemented_nid_no_patch.
sceAudiodecUnregisterCodec (libSceAudiodec.native) - (context, 32-bit type) from @BunnyFl's firmware 13.42 run under an emulator with imports stubbed; the measured local checks are in: a null context returns 0x807F0002, a type outside 1, 2, 3, 4, 6, 10, 11, 12 returns 0x807F0001, and types 11/12 with their flag clear (u32 at +8/+0xC from the rwlock handle at (context + 0xF) & ~7) return 0x8093000A with no service call. Still unimplemented, so a non-null accepted input throws: the documented Ajm/Ajmi service calls for accepted types and flag-set 11/12, the write lock, and the flag-set path. Only this module exports it, as the 13.60 inventory and the 13.42 module agree
sceAudiodecGetAjmContext (libSceAudiodec.native) - (context, uint32_t* ajmi, uint32_t* ajm) from the same 13.42 run, not measured on a console: a null context returns 0x807F0002 and writes nothing, otherwise the two 32-bit ids at offsets 0 and 4 of the context go to the outputs that are not null and the call returns 0, with no lock, no service call and no check that sceAudiodecInitialize filled the context. Only this module exports it, so libSceAudiodec does not