A 0.01ms keyframe still only STARTS on the frame after the element is inserted,
so the panel's first painted frame was the keyframe's `from` state (opacity 0)
even with prefers-reduced-motion: reduce. Verified live on dev by the harness's
8a check ('panel fully opaque on the first frame' -> measured 0).
`animation: none` paints the element's natural style immediately and removes
the row stagger's delays with it.
Also decides the panel's open/close from an imperative `phase` ref instead of
the render closure, so a close+re-open landing in ONE task re-opens the panel
instead of being swallowed as a second close (harness 6b).
And fixes the harness itself: it sampled the panel synchronously right after a
programmatic .click(), i.e. before React's commit, which reported 'panel never
mounted' for a working panel (checks 1/2/3a/3b/8a); the sample now starts on the
first animation frame, and the gates scan every sample. It also fell back from
channel='chrome' (not installed on the verifying VPS) to bundled chromium.
sapl-admin
f18c961e3e
