`dropAll` clears every scoped entry in both storage areas; `dropProbes` clears detection's well-known answers, which keep their own policy and are the only cache nothing else empties. Refresh bypasses caches on the path it walks; neither of these has had a caller until now. Both sweep by prefix rather than clearing an area, because both areas also hold things that are not caches — the account mirror, the reader choice, the per-tab detection states — and dropping those would break rather than refill. Both return a count so a caller can say what went. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>