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/SendRoomEvent.tsx

@@ -1,6 +1,6 @@
 import React, { useCallback, useRef, useState, FormEventHandler, useEffect } from 'react';
 import { MatrixError } from 'matrix-js-sdk';
-import { Box, Chip, IconButton, Text, config, Button, Spinner, color, TextAreaComponent as TextArea, Input } from 'folds';
+import { Box, Chip, IconButton, Text, config, Button, Spinner, color, TextArea, Input } from 'folds';
 import { Icon, Icons } from '../../../components/icons';
 import { Page, PageHeader } from '../../../components/page';
 import { useMatrixClient } from '../../../hooks/useMatrixClient';
@@ -171,7 +171,7 @@ export function SendRoomEvent({ type, stateKey, requestClose }: SendRoomEventPro
             <Box shrink="No">
               <Text size="L400">JSON Content</Text>
             </Box>
-            <TextAreaComponent
+            <TextArea
               ref={textAreaRef}
               name="contentTextArea"
               style={{ fontFamily: 'monospace' }}