No change in decoding. An aac-encode build in the next PR needs the
split_adts_upto re-export behind aac-decode, and ID_END only in tests.
Docs say the lookahead's headers give an ADTS stream's configuration, that AAC in
CAF still goes through symphonia, and that ProgramConfig is not #[non_exhaustive].
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>