Applied as-is. When --refresh is set, a download that still fails after four attempts throws instead of returning the older cached file, so one build cannot mix a new table with an old one. --offline and a warm cache without --refresh are unchanged. Files already written to the cache stay; generated data/ and the previous report are left in place.
Tests: node --test test/build-data-refresh.test.js — 11 pass, 0 fail.
