* docs(registry,skills): surface code-highlight 0-based indexing and opacity-reveal sweep guidance
From the 2026-07-14 CLI feedback digest (skills-owner action): a user
building code teaching videos hit two authoring gaps.
1. code-highlight's `line` is intentionally zero-based (`line: 1` =
second displayed line) but the warning lived only in pr-to-video's
code-vocabulary reference — nowhere an author actually touches the
value. Call it out at the block-use sites: the `__BLOCK` declaration
itself, the registry-item description, and the motion-graphics
catalog map.
2. Opacity-only code-typing tripped `sweep_static` for that user, who
worked around it with a slow host y-drift. The sweep fingerprint
does include per-element opacity, so document the actual trap (a
reveal that settles before the sampled window, then holds a static
frame) and the idiomatic fixes (spread the reveal / keep a blinking
caret alive) in the check reference — and pin the fingerprint's
opacity sensitivity with a regression test covering both the
visibility-floor crossing and a mid-fade value change.
* docs(catalog): regenerate code-highlight page from updated registry-item description
Only the code-highlight page is committed: a full generate-catalog-pages
run also surfaces ~34 blocks missing from the git-tracked catalog index
(pre-existing drift on main), which belongs in its own chore PR.
WaterrrForever
c8d13af9b2