Add emoji confetti bursts and component playground.

Support app.relay.emoji_confetti on jumbo emoji clicks with canvas physics,
per-emoji particle profiles, and a fixed overlay that does not affect scroll.
Also add a Vite playground for live component previews and theme hover preview.

src/app/components/AccountDataEditor.tsx

@@ -1,5 +1,5 @@
 import React, { FormEventHandler, useCallback, useEffect, useMemo, useRef, useState } from 'react';
-import { Box, Text, IconButton, Input, Button, TextAreaComponent as TextArea, color, Spinner, Chip, Scroll, config } from 'folds';
+import { Box, Text, IconButton, Input, Button, TextArea, color, Spinner, Chip, Scroll, config } from 'folds';
 import { Icon, Icons } from './icons';
 import { MatrixError } from 'matrix-js-sdk';
 import { Cursor } from '../plugins/text-area';
@@ -154,7 +154,7 @@ function AccountDataEdit({
         <Box shrink="No">
           <Text size="L400">JSON Content</Text>
         </Box>
-        <TextAreaComponent
+        <TextArea
           ref={textAreaRef}
           name="contentTextArea"
           style={{