List the sites this key can see, with health

Every site this key can see, each with its health, what lowers its score, its billing state and its latest crawl. Call it first: it gives the site ids the other capabilities take (a domain works too). A site missing here means this key cannot reach it, not that it does not exist. Quote a score with health.coverage beside it, never alone: it is a claim about the pages the crawl read. A null score or inconclusive is never a healthy site, and zero findings is never evidence of health. A site with billing.read_only refuses crawls and verification: give your human billing.checkout_url. Next: sites_get for one site's detail, issues_list for its issue queue.