- Footage can store custom proxy parameters (width/height/crf/preset/
extension/audio) that override the global settings; they are
serialized with the project and used by every generation entry point
via Footage::GetEffectiveProxyParams()
- Proxies now include the source audio streams (AAC) unless disabled;
the proxy filename records the audio flag and offline audio rendering
decodes from the proxy when present
- ProxyTask resolves ffmpeg from the new FFmpegPath config key first,
then PATH, then common install locations (e.g. Homebrew on macOS),
instead of relying on PATH only; the error message points at the
preferences when no executable is found
- ProxyTask::BuildArguments() is extracted for testability
- Add ProxyIncludeAudio and FFmpegPath config defaults
- Add regression tests for the filename audio marker, config-backed
params, ffmpeg resolution, argument building, and custom-param
persistence