Phase 2 — the engine:
- core/video/download_monitor.py: a daemon thread polls slskd for active video
downloads, updates progress, and on completion MOVES the file from the shared
download folder into the per-type library folder + marks it completed. The
per-download decision (process_download) is pure (fs + slskd injected) — 6 tests.
- POST /downloads/grab: validates (Soulseek-only v1), resolves the target library by
kind, starts the slskd download, records the row, lazily starts the monitor.
- GET /downloads/active (list + ensure monitor running) · POST /downloads/clear
(drop finished).
14 tests, isolation guard + ruff clean. Grab button + Downloads page next.
