Embedded in the Omics Portal the SPA sits to the right of the portal sidebar,
but dialogs used `fixed left-1/2` — centered on the whole browser window, so
gates rendered visibly off-center (overlapping the sidebar).
- AppShell publishes the app area's horizontal geometry (--app-area-left/width)
as CSS vars on <html> via ResizeObserver + window resize.
- DialogContent centers on those vars (falls back to the viewport when the app
is standalone, where the two coincide).
- ArtifactGateWidget: narrower — cap at 52rem instead of 70vw.
- tools/replay: resume now returns {id, alreadyActive} JSON — the post-f979ada
frontend reads result.alreadyActive and a bare 204 broke replay resume.
Verified on the replay harness: with a simulated 300px portal sidebar the gate
centers on the app area (center 790 = 300 + 980/2); standalone unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
marcopanandClaude Fable 5
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