fix(ui): address review feedback on #9432

Empty the changeset (Mosaic has no consumer-visible surface), match the
`[clerk] ` prefix the package's other dev warnings use, and give the
stack veil the phone band's `slow` duration so it stays in step with the
recede it accompanies.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: maxyinger

.changeset/dialog-stack-motion.md

@@ -1,5 +1,2 @@
 ---
-'@clerk/ui': patch
 ---
-
-Mosaic `Dialog` now distinguishes a stack — successive `prompt` dialogs, such as a confirmation over the form it is confirming — from a dialog opened over a `panel` or `card`. A stacked prompt paints no backdrop of its own, so the page no longer darkens further with every level; the prompt beneath it dims and recedes instead. Dialogs opened over a `panel` or `card` are unchanged. Opening a `panel` or `card` inside another dialog now warns in development.

packages/ui/src/mosaic/components/dialog/dialog.styles.ts

@@ -180,7 +180,13 @@ export const styles = stylex.create({
       opacity: 'var(--_cl-stack-veil, 0)',
       pointerEvents: 'none',
       position: 'absolute',
-      transitionDuration: durationVars['--cl-duration-base'],
+      // Tracks the recede it accompanies rather than standing on its own: the two are halves of
+      // one gesture, and the phone band runs the transform at `slow`. Pinning the veil at `base`
+      // there finishes the dim 100ms before the surface stops moving, in both directions.
+      transitionDuration: {
+        default: durationVars['--cl-duration-base'],
+        '@media (max-width: 47.99rem)': durationVars['--cl-duration-slow'],
+      },
       transitionProperty: 'opacity',
       transitionTimingFunction: easingVars['--cl-ease-enter'],
       zIndex: 1,

packages/ui/src/mosaic/components/dialog/dialog.tsx

@@ -246,7 +246,7 @@ function useNestedSizeWarning(isNestedInDialog: boolean, size: DialogSize) {
       return;
     }
     console.warn(
-      `Mosaic: a Dialog opened inside another Dialog should be size="prompt", but this one is size="${size}". ` +
+      `[clerk] a Dialog opened inside another Dialog should be size="prompt", but this one is size="${size}". ` +
         'Only prompts are meant to open over another dialog; the rest are root-level surfaces.',
     );
   }, [isNestedInDialog, size]);