Extract clampHeight + isTrustedHeightMessage + the HTML_EMBED_SANDBOX token
constant from the NodeView and test them: clamp bounds; reject a resize message
from a foreign window / wrong type / NaN/Infinity; accept a valid same-source
finite message; assert the sandbox is exactly 'allow-scripts allow-popups
allow-forms' (no allow-same-origin) and rendered via srcDoc (not src).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>