Extract a page's structured data: JSON-LD (schema.org), Open Graph tags, and best-effort microdata. Returns the parsed JSON-LD objects, detected schema.org types (Product, Offer, Review, Event, Recipe, Article…), microdata items and the og:* map. Send inline {html} or a public {url} (SSRF-checked). Malformed JSON-LD yields a {parseError} entry, never a crash. Microdata is best-effort; JSON-LD is the reliable path. Max 5 MB.