Passing a Cloudflare challenge mints an HttpOnly cf_clearance cookie bound to
IP+UA. 'chrome-use cf-status' (aliases cf/cloudflare-status/clearance) reports
whether the active page is currently a CF challenge and whether a still-valid
cf_clearance exists (read via CDP — HttpOnly is invisible to document.cookie),
plus CF_VERIFIED_DEVICE trust, and a recommendation: proceed (already cleared,
don't re-solve) / solve (challenge up, no clearance) / reissue (clearance present
but page still blocks → IP/UA drifted). Lets an agent avoid re-solving what it
already cleared — the persistence optimization. Pure helpers unit-tested; live
-verified on a real cf_clearance.