Research loop fails on Windows due to Unix-only fcntl import

Labels: bug, platform:windows, researcher-os, good first issue

researcher/scripts/loop_common.py imports and uses fcntl.flock at the top level. fcntl is not available on Windows, so loop_step.py, loop_discover.py, loop_daily.py, and loop_status.py all crash with ModuleNotFoundError on import.

Reproduction: python -c "from researcher.scripts.loop_common import queue_lock" Impact: The entire autonomous research loop is unusable on Windows, contradicting the repo's platform-agnostic claims.

Suggested fix:

• Replace fcntl with a cross-platform lock (e.g., filelock, portalocker, or a threading.Lock fallback), or document the Unix-only limitation.