💫(frontend) wave icon when a participant raises her hand

Minor enhancement, add some CSS animation to wave a newly
raised hand. Inspired by GMeet.

src/frontend/panda.config.ts

@@ -75,6 +75,12 @@ const config: Config = {
         '50%': { height: '4px' },
         '100%': { height: '8px' },
       },
+      wave_hand: {
+        '0%': { transform: 'rotate(0deg)' },
+        '20%': { transform: 'rotate(-20deg)' },
+        '80%': { transform: 'rotate(20deg)' },
+        '100%': { transform: 'rotate(0)' },
+      },
     },
     tokens: defineTokens({
       /* we take a few things from the panda preset but for now we clear out some stuff.

src/frontend/src/features/rooms/livekit/components/ParticipantTile.tsx

@@ -133,6 +133,9 @@ export const ParticipantTile: (
                           size={16}
                           style={{
                             marginInlineEnd: '.25rem', // fixme - match TrackMutedIndicator styling
+                            animationDuration: '300ms',
+                            animationName: 'wave_hand',
+                            animationIterationCount: '2',
                           }}
                         />
                       )}