Resolve a website's best icon: parses <head> for link rel=icon / apple-touch-icon / mask-icon, reads a linked web app manifest's icons, and adds the /favicon.ico fallback, then ranks them (scalable/large first). Returns the best iconUrl plus all ranked candidates with rel/sizes/type/source. The URL is SSRF-checked; fetches are capped. For agents building directories or UIs.