GHSA-x4hg-hfwf-p9mw: @asymmetric-effort/nogginlessdom vulnerable to ReDoS via user-controlled regex in HTMLInputElement pattern validation

The HTMLInputElement.checkValidity() method constructed a RegExp directly from the user-controlled pattern property without any sanitization or timeout protection. This allowed an attacker to inject a regex with catastrophic backtracking, freezing the event loop.