Download Job Lifecycle

queued -> downloading -> completed
                     \-> failed
queued -> cancelled
downloading -> cancelled

Jobs are retained for 24 hours after completion (override via top-level download_job_retention_hours in unshackle.yaml). The server runs up to 2 concurrent download jobs by default; override via top-level max_concurrent_downloads. This is independent of serve.downloads, which controls parallel tracks within a single job.

Remote sessions are managed by SessionStore (unshackle/core/api/session_store.py); idle sessions and their InputBridge instances are cleaned up by a background loop started/stopped with the app lifecycle.