perf(studio): draw toasts on an opaque surface without backdrop blur

Author: miguel-heygen

packages/studio/src/components/StudioToast.tsx

@@ -46,5 +46,6 @@ export function StudioToast({ message, tone, leaving, onDismiss }: StudioToastPr
 }
 
 export function toastSurface(isError: boolean): string {
-  return `border shadow-popover backdrop-blur-md ${isError ? "border-danger/40 bg-raised" : "border-border bg-raised/95"}`;
+  // Opaque, no backdrop blur: a blur re-rasters what is behind it every frame of the enter animation.
+  return `border shadow-popover bg-raised ${isError ? "border-danger/40" : "border-border"}`;
 }