8 tests locking in security-critical behavior of sanitizeCustomHtml /
sanitizeText: script-content removal, event-handler stripping, javascript:
link neutralization, anchor hardening (noreferrer/noopener/_blank), non-mxc
<img> → link conversion, and the N100 <pre class> language-* restriction.
Verified against actual sanitize-html behavior. Suite now 27 tests.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
