- New video-processor.ts: ffmpeg/ffprobe remux that keeps only the German
audio track (by language tag, with safe fallbacks) and strips the ".DL."
marker from the filename
- Runs after extraction in both the deferred and hybrid post-process paths,
inside the per-package file-op chain; abortable, disk-space checked,
mtime-preserving, atomic temp->replace so the original is never lost
- System ffmpeg via PATH / RD_FFMPEG_BIN; toggle + track-mode select in settings
