fix: replace PreviewModal motion with CSS animation, add motion test mock

- PreviewModal no longer uses motion/react — prevents test failures from
  AnimatePresence exit animations never completing in test env
- Add CSS animations for .ds-modal-backdrop (fade-in) and .ds-modal (scale-in)
- Add vitest alias to mock motion/react so AnimatePresence in other
  components (UpdaterPopup, ExamplesTab) completes synchronously in tests

apps/web/src/components/PreviewModal.tsx

@@ -1,5 +1,4 @@
 import { useEffect, useMemo, useRef, useState, type ReactNode } from 'react';
-import { motion } from 'motion/react';
 import { useT } from '../i18n';
 import { copyToClipboard } from '../lib/copy-to-clipboard';
 import {
@@ -12,7 +11,6 @@ import {
 } from '../runtime/exports';
 import { buildSrcdoc } from '../runtime/srcdoc';
 import { Icon } from './Icon';
-import { modalOverlay, modalContent } from '../motion';
 
 export interface PreviewView {
   id: string;
@@ -471,22 +469,14 @@ export function PreviewModal({
   const canOpenTemplateShareMenu = canExportFiles || Boolean(previewShareUrl);
 
   return (
-    <motion.div
+    <div
       className="ds-modal-backdrop"
       role="dialog"
       aria-modal="true"
       aria-label={`${title} preview`}
-      variants={modalOverlay}
-      initial="hidden"
-      animate="visible"
-      exit="exit"
     >
-      <motion.div
+      <div
         className={`ds-modal ${fullscreen ? 'ds-modal-fullscreen' : ''}`}
-        variants={modalContent}
-        initial="hidden"
-        animate="visible"
-        exit="exit"
       >
         <header className="ds-modal-header">
           <div className="ds-modal-header-top">
@@ -941,7 +931,7 @@ export function PreviewModal({
             </aside>
           ) : null}
         </div>
-      </motion.div>
-    </motion.div>
+      </div>
+    </div>
   );
 }

apps/web/src/styles/entrance.css

@@ -462,6 +462,18 @@
    ================================================================ */
 
 
+/* ================================================================
+   Preview modal
+   ================================================================ */
+
+.ds-modal-backdrop {
+  animation: od-fade-in 200ms cubic-bezier(0.23, 1, 0.32, 1) both;
+}
+
+.ds-modal {
+  animation: od-scale-in 250ms cubic-bezier(0.23, 1, 0.32, 1) both;
+}
+
 /* ================================================================
    Plugin detail view
    ================================================================ */

apps/web/tests/helpers/motion-mock.tsx

@@ -0,0 +1,32 @@
+import { forwardRef, type ComponentProps, type ElementType } from 'react';
+
+function AnimatePresence({ children }: { children?: React.ReactNode }) {
+  return <>{children}</>;
+}
+
+const motionHandler: ProxyHandler<object> = {
+  get(_target, prop: string) {
+    const Component = forwardRef<unknown, ComponentProps<ElementType>>((props, ref) => {
+      const {
+        variants: _variants,
+        initial: _initial,
+        animate: _animate,
+        exit: _exit,
+        whileHover: _whileHover,
+        whileTap: _whileTap,
+        transition: _transition,
+        layout: _layout,
+        layoutId: _layoutId,
+        ...rest
+      } = props as Record<string, unknown>;
+      const Tag = prop as ElementType;
+      return <Tag ref={ref} {...rest} />;
+    });
+    Component.displayName = `motion.${prop}`;
+    return Component;
+  },
+};
+
+const motion = new Proxy({}, motionHandler);
+
+export { AnimatePresence, motion };

apps/web/vitest.config.ts

@@ -1,6 +1,12 @@
+import { resolve } from 'node:path';
 import { defineConfig } from 'vitest/config';
 
 export default defineConfig({
+  resolve: {
+    alias: {
+      'motion/react': resolve(__dirname, 'tests/helpers/motion-mock.tsx'),
+    },
+  },
   test: {
     environment: 'node',
     include: ['tests/**/*.test.{ts,tsx}'],