Fix mobile chip-strip overlap, reveal-replay stagger, scroll-linked text-fill

Three clone-fidelity fixes from manual review of the acceptance screenshots.

Fix 1 — mobile nav chip-strip overlap (generate/css.ts). A horizontally
scrollable flex strip (overflow-x:auto flex <ul>) of nowrap chips collapsed
because the base viewport reported min-width:0px on the chips (a mobile-only
strip that is 0-wide at desktop), so the generator emitted `min-w-0`, letting
the chips shrink below their content instead of overflowing — the nowrap text
then collided. Suppress `min-w-0` for a nowrap flex item whose flex parent
scrolls horizontally; scoped away from legitimate min-w-0 truncation (whose
parent does not scroll-x). Verified on a fresh ooni.com clone: 0 chip overlaps
at 375, scrollWidth 776 > clientWidth 375.

Fix 2 — reveal-replay stagger leaves tiles unpainted (generate/motion.ts).
DittoMotion re-hid each revealed element and replayed its entrance on
scroll-into-view preserving the captured delay/duration, so a fast scroll /
full-page screenshot caught most grid tiles mid-entrance. Cap the replayed
delay (<=300ms) and duration (<=600ms), settle each tile per-element a bounded
time after it enters view, and make the global failsafe settle (not re-animate)
so nothing stays hidden. Validator settle path (__dittoMotionStop) unchanged.
Verified: cropin cotton renders 12/12 crop tiles in a normal full-page pass;
motion gate reveals 24/24.

Fix 3 — scroll-linked text-fill frozen at end state (capture/stabilize.ts,
capture/capture.ts, generate/css.ts). A view-timeline text-fill
(animation-duration resolves to `auto`) was baked filled: the clone has no
scroll timeline, so emitting the animation made it jump to its end keyframe via
fill-mode:both. Capture-side, cancel scroll/view-timeline animations before each
snapshot so the DOM records the at-rest state; generation-side, suppress the
animation-* props when animation-duration is `auto` (we render the at-rest
state, never replay a scroll-linked animation). Teach the motion gate to exclude
these from the static-CSS expectation so the gate stays honest. Verified on a
fresh ooni clone: the "world's no.1 pizza ovens" em is white/gray (rgb 240,240,
240), not filled yellow, at rest; motion gate still passes.

Tests: +7 fixtures (css scroll-strip + scroll-timeline, reveal-replay caps,
motion-gate scroll-timeline exclusion); 123/123 compiler tests green, full test
suite green, typecheck clean. No gate regression on the fresh ooni run vs the
20260704-024247 baseline (all gate pass/fail unchanged; perceptual within
0.0004; motion restored to pass).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

compiler/test/motionGate.test.ts

@@ -9,7 +9,7 @@ import { missingHarnessDeps } from "../src/validate/render.js";
 
 // Minimal IRNode factory — collectExpectedCss only reads id, computedByVp[vp].animation*,
 // and children, so we build just those fields and cast.
-function node(id: string, anim: { animationName?: string; animationIterationCount?: string } | null, children: IRNode[] = []): IRNode {
+function node(id: string, anim: { animationName?: string; animationIterationCount?: string; animationDuration?: string } | null, children: IRNode[] = []): IRNode {
   return {
     id,
     tag: "div",
@@ -44,6 +44,20 @@ describe("motion gate — CSS entrance / reveal-replay accounting", () => {
     assert.deepEqual(fade.names, ["fadeInUp"]);
   });
 
+  it("collectExpectedCss EXCLUDES a scroll/view-timeline animation (animation-duration:auto)", () => {
+    // Fix 3: the ooni text-fill em (animation-timeline:view → computed animation-duration:auto)
+    // is intentionally NOT emitted (we render the at-rest state, not a scroll replay). It must be
+    // excluded from the static-CSS expectation, not counted as an owed-but-missing animation.
+    const tree = ir(
+      node("n0", null, [
+        node("n358", { animationName: "fillAnimation", animationDuration: "auto", animationIterationCount: "1" }),
+        node("n4", { animationName: "spin", animationDuration: "1s", animationIterationCount: "infinite" }),
+      ]),
+    );
+    const got = collectExpectedCss(tree);
+    assert.deepEqual(got.map((e) => e.cid), ["n4"], "scroll-timeline node n358 must be excluded");
+  });
+
   it("cssReplayedByReveal excludes a captured entrance the clone replays via a reveal", () => {
     // The cropin regression: n464's fadeInUp is driven by a DittoMotion reveal, so the static
     // animation-name is deliberately NOT emitted — it must NOT fail emitted=false.