Self-keepalive while jobs are in flight to prevent autosleep mid-parse

Add job-style /parse/jobs API: submit-and-poll, durable across restarts

Stream /parse as NDJSON: heartbeat every 5s, terminal result event last

Redirect ~/.cache to the bucket so datalab models persist

Sync _project docs to deployed reality

Scaffold marker: FastAPI wrapper around marker-pdf for HF Space

Initial project scaffold from sappcode template