DOMPurify: Hook mutation of `data.allowedTags` / `data.allowedAttributes` permanently pollutes `DEFAULT_ALLOWED_TAGS` / `DEFAULT_ALLOWED_ATTR`

Hook mutation of data.allowedTags / data.allowedAttributes permanently pollutes DEFAULTALLOWEDTAGS / DEFAULTALLOWEDATTR CWE: CWE-501 Trust Boundary Violation — hook-scoped mutation leaks to global default sets via CWE-693 Protection Mechanism Failure — the default allow-list is silently widened f...