All block-media kinds except .audio now lay out edge-to-edge (0 inset) with
cornerRadius 0; the bubble's existing rounded containerNode clip rounds media at
the bubble edge. Small images keep natural size (not upscaled); captions stay
inset. Shared instantPageV2MediaFrame helper + flush flag on the two media
layout helpers. V1 unchanged. Invariants documented in docs/instantpage-richtext.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
isaacandClaude Opus 4.8
9b1573e87e