Adds precompiled Linux x86_64 binaries for yt-dlp and ffmpeg under bin/.
The processor resolves yt-dlp from bin/ when present, falling back to PATH.
ffmpeg is passed via --ffmpeg-location so yt-dlp uses the bundled binary on o2switch.
BIN_DIR is configurable via env var.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
