Fetch a site's robots.txt and evaluate crawl permissions: given a URL (plus optional extra paths) and a user-agent, return whether each path is allowed or disallowed, the rule that matched, the user-agent group, the crawl-delay and any declared sitemaps. Implements the Robots Exclusion Protocol (RFC 9309) with longest-match-wins, Allow-over-Disallow tie-breaking and * / $ wildcards.