The build check mywant-gui

web/scripts/check-overlays.mjs fails the build when a piece of overlay design is written out by hand outside src/components/overlay. It is how two dozen overlays, each with its own idea of what "Cancel" looks like, became one.

node scripts/check-overlays.mjs            # checks ./src
node scripts/check-overlays.mjs path/src   # checks another tree
npm run check:overlays

What it looks for

Found outside the library	Use instead
The overlay surface classes (bg-slate-900 border border-slate-600)	OverlayBubble, or useOverlayDesign().surface for another shape
The overlay outline colour (rgb(71 85 105)) — a hand-drawn tail	OverlayBubble, or useOverlayDesign().tailColor
The entrance animation names (quickActionsIn, quickActionBtnIn) as strings	useOverlayDesign().enterAnimation / .cellEnterAnimation, or OverlayCell

CSS files are skipped (the keyframes are defined in one), and so is the library itself.

The type system covers the rest: OverlayItem and a card's EntityCardAction have no class-name field, only tone, so an item cannot say how it is painted.

Where it runs mywant-gui

npm run build in web/ — and so make install — runs it before tsc.

Where it runs mywant-guiex

The canvas extension runs the same script, from its submodule, over its own source before its type check:

build-extension:
	cd web && node ../mywant-gui/web/scripts/check-overlays.mjs src && npx tsc --noEmit -p . && …

One script, two trees: the rule is the app's, and the extension is held to it.