Replace the class-level Track.download monkeypatch with a per-job progress sink threaded through dl.result(). The API now reports a single aggregate signal instead of each track's bouncing 0-100%:
- bitrate-weighted completion so video/audio dominate subtitles
- completed_tracks/total_tracks counts and active_tracks labels (e.g. "video 2160p DV", "audio en-US 5.1")
- downloads fill 0-90%; repackaging (when needed) and a "muxing" stage carry it to 100% so post-download work is no longer frozen at 100%
- monotonic throughout (handles the download->decrypt callable reuse)
Also:
- accept "HDR10P" as the canonical API range value ("HDR10+" still works)
- declare AUTH_METHODS opt-in on the Service base
- raise typed APIError (WORKER_ERROR/DOWNLOAD_ERROR) from the worker path
- move the progress helpers to unshackle/core/api/progress.py
