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/room/RoomTimeline.tsx

@@ -137,6 +137,8 @@ import {
   PAARROT_CAROUSEL_TOTAL_PROPERTY_NAME,
   PAARROT_CAROUSEL_UUID_PROPERTY_NAME,
 } from '../../../types/matrix/common';
+import { EmojiConfettiOverlay } from './emoji-confetti/EmojiConfettiOverlay';
+import { useJumboEmojiConfetti } from './emoji-confetti/useJumboEmojiConfetti';
 
 /** Information about a call member event for grouping */
 interface CallEventInfo {
@@ -582,6 +584,8 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
   );
   const [showHiddenEvents] = useSetting(settingsAtom, 'showHiddenEvents');
   const [showDeveloperTools] = useSetting(settingsAtom, 'developerTools');
+  const { bursts: emojiConfettiBursts, removeBurst: removeEmojiConfettiBurst, handleJumboEmojiClick } =
+    useJumboEmojiConfetti(room);
 
   const [hour24Clock] = useSetting(settingsAtom, 'hour24Clock');
   const [dateFormatString] = useSetting(settingsAtom, 'dateFormatString');
@@ -1597,6 +1601,8 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
                 linkifyOpts={linkifyOpts}
                 outlineAttachment={messageLayout === MessageLayout.Bubble}
                 disabledEmbedPatterns={combinedEmbedFilters}
+                targetEventId={mEventId}
+                onJumboEmojiClick={handleJumboEmojiClick}
               />
             )}
           </Message>
@@ -1705,6 +1711,8 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
                       linkifyOpts={linkifyOpts}
                       outlineAttachment={messageLayout === MessageLayout.Bubble}
                       disabledEmbedPatterns={combinedEmbedFilters}
+                      targetEventId={mEventId}
+                      onJumboEmojiClick={handleJumboEmojiClick}
                     />
                   );
                 }
@@ -2002,6 +2010,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
         // Return special marker for call event (will be handled by eventRenderer)
         return 'CALL_EVENT_PENDING' as unknown as React.ReactNode;
       },
+      [MessageEvent.RelayEmojiConfetti]: () => null,
     },
     (mEventId, mEvent, item) => {
       if (!showHiddenEvents) return null;
@@ -2704,6 +2713,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
           </Box>
         </TimelineFloat>
       )}
+      <EmojiConfettiOverlay bursts={emojiConfettiBursts} onBurstComplete={removeEmojiConfettiBurst} />
     </Box>
   );
 }