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/features/common-settings/developer-tools/StateEventEditor.tsx

@@ -1,5 +1,5 @@
 import React, { FormEventHandler, useCallback, useEffect, useMemo, useRef, useState } from 'react';
-import { Box, Text, IconButton, Chip, Scroll, config, TextAreaComponent as TextArea, color, Spinner, Button } from 'folds';
+import { Box, Text, IconButton, Chip, Scroll, config, TextArea, color, Spinner, Button } from 'folds';
 import { Icon, Icons } from '../../../components/icons';
 import { MatrixError } from 'matrix-js-sdk';
 import { Page, PageHeader } from '../../../components/page';
@@ -153,7 +153,7 @@ function StateEventEdit({ type, stateKey, content, requestClose }: StateEventEdi
         <Box shrink="No">
           <Text size="L400">JSON Content</Text>
         </Box>
-        <TextAreaComponent
+        <TextArea
           ref={textAreaRef}
           name="contentTextArea"
           style={{ fontFamily: 'monospace' }}