Draw the colour disc inside its tile rather than past it

The disc was sized against its parents in percentages, and every box
between it and the tile is sized by what is in it — so the chain never
resolved, the brightness slider grew, and the tile scrolled with half a
disc showing. Container units are the tile's own height whatever sits in
between, so the widget now fits exactly.

Two guards behind it, since both are things a picture can fail silently:
nothing on a panel of pictures may overflow its tile, and Touch has to
actually make a control bigger while leaving what it publishes alone.

frontend/src/components/Dashboard/ui/glass/Data.tsx

@@ -177,7 +177,7 @@ export function ColorDisk({
   })
   const [hue, saturation, brightness] = hsv
   return (
-    <div className="grid h-full min-h-0 grid-cols-[minmax(0,1fr)_auto] items-center justify-items-center gap-3">
+    <div className="dui-color">
       <div
         {...discProps}
         data-testid={TESTID.disc}