Metadata probe outside the retry loop #279

Location: download.py:228
Severity: HIGH

The pre-download extract_info(download=False) duration check has no retry and no explicit socket timeout. A transient network blip at that instant fails the job immediately, even though the actual download has a 3-attempt backoff.
Wrap the metadata fetch in the same _is_retriable/backoff loop and set socket_timeout in ydl_opts.

From the health report. Part of #273 (Phase 2 — Resilience).