Problem: Premiere's "AAC Audio" format has no FilmCraft equivalent. AAC
was only written inside H.264 / H.265 / AV1 movies; the only audio-only
exports were Waveform Audio and AIFF.
Fix: a new `aac` export format ("AAC Audio") that encodes the sequence
mix with the existing AAC-LC encoder into an MPEG-4 audio file (.m4a,
encoder delay in an edit list), or a raw ADTS stream when the path ends
in .aac. Bitrate, sample rate, channels and loudness normalisation follow
the audio settings. Adds an "AAC Audio 48 kHz 320 kbps" Audio Only
preset, CLI extension guessing (.m4a / .aac), es/fr/ja/zh-cn strings, and
updates G13 (also noting ProRes 4444 / XQ is already in the export UI).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>