Tests for SizeCappedBuffer (eviction, export, summary), validateTempPath
(TEMP_DIR only, rejects cwd), command registration (all new commands in
correct scope sets), and MIME mapping source checks.
Rich HTML fixture with: standard images, lazy-loaded images, srcset,
video with sources + HLS, audio, CSS background-images, JSON-LD,
Open Graph, Twitter Cards, and meta tags.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Garry Tan