Extract emails from text

Finds everything shaped like an email address, removes duplicates and lists them one per line, keeping the order they first appeared in.

The pattern is deliberately permissive rather than validating. A genuinely RFC-compliant email regex is thousands of characters long and still rejects addresses that work, so trying to validate here would silently drop real addresses. Finding things shaped like an address and letting you look at the list is the honest approach — a false positive is obvious to a human and a missing address is not. Worth remembering that a list of addresses scraped from a page is personal data under GDPR and similar laws: having extracted it does not make sending to it lawful, and unsolicited mail to scraped addresses is exactly what the rules exist to prevent.