Per review feedback: CDFER's upstream scraper pipeline has stalled for weeks
(broken cart API + a bug in their scraper), so a "fresh download" can still be
old data. Compute the catalog age from the source Last-Modified header, expose
catalog_age_days, and emit a stale=True + warning when older than 14 days that
points users to source='yaqwsx' (fresh, needs 7z) or source='official'. Surface
the warning in the MCP tool output.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>