Addresses the still-outstanding review concerns from merged PRs #1569 / #1570 /
#1572 not already hoisted into #1573.
WS-B (#1569):
- validateVariables requires discriminant fields for object-valued font/image
({name,source} / {url}); a {name:42} font or {foo:42} image previously passed
runtime validation and surfaced as a bogus font-family / missing image.
- Dropped ImageValue's [key:string]:unknown index signature (let any {url}-shaped
object through, swallowed typos); explicit alt?/fit? instead.
- Documented the OverrideSet widening for SDK consumers.
WS-C (#1570):
- getElementTimings caches parsed GSAP labels by exact script text (avoids a full
acorn re-parse per read; content-key invalidates on edit).
- Documented end-inclusive label window + best-effort extractGsapLabels catch.
WS-3.C (#1572):
- Added typed Composition.addWithKeyframes / replaceWithKeyframes (was asymmetric
with addGsapTween; Studio had to use raw dispatch).
- Extracted shared KeyframeSpec type; documented position as seconds/number-only.
Gates: build + core 18/18 + sdk 19/19 + oxlint + oxfmt + fallow + typecheck all green.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>