When a download's tmux pane is gone, the status endpoint trusted only the
HF-cache probe to tell completed from stopped. The probe derives its cache
root from its own environment, but the download runner exports
HF_HOME=<local_dir> (the #2722 fix), so custom-dir downloads land in
<local_dir>/hub where the probe never looks - and ollama pulls don't touch
the HF cache at all. Finished downloads were reported as stopped forever,
and tasks already persisted as completed were demoted back to stopped on
the next poll. This is the backend half of #3897, deliberately left out of
the frontend fix in #4000.
- honor the conclusive runner markers first: DOWNLOAD_OK -> completed
(keeping the "Fetching 0 files" error guard), DOWNLOAD_FAILED -> error
- pass the task's local_dir through to the cache probes so they check the
cache the download actually wrote to, keeping the env-var fallback for
default-cache downloads
- move the probe scripts and marker classification into
routes/cookbook_output.py (dependency-free) with behavioral tests
Fixes#4017
Ashvin
23837f4571