Emoji reactions on songs

React to a friend's current song or any of their recent plays: tap an
emoji to add yours (or take it back), "☺+" for the quick six, and a full
picker with search and categories (Unicode emoji up to 13.1, generated
into the shared package so web and mobile match). One reaction per person
per play; a new one replaces the old. Chips show counts and, on hover/
long label, who reacted; yours is highlighted. Listeners and followers get
the update live. Not on your own plays, not across a block (blocking also
clears reactions between the two people).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

apps/api/src/app.ts

@@ -17,6 +17,7 @@ import { avatarRoutes } from './routes/avatars';
 import { connectionRoutes } from './routes/connections';
 import { deviceRoutes } from './routes/devices';
 import { meRoutes } from './routes/me';
+import { reactionRoutes } from './routes/reactions';
 import { realtimeRoutes } from './routes/realtime';
 import { safetyRoutes } from './routes/safety';
 import { trackRoutes } from './routes/tracks';
@@ -74,6 +75,7 @@ export async function buildApp({ logger = true, rateLimits = true }: { logger?:
   await app.register(safetyRoutes);
   await app.register(adminRoutes);
   await app.register(trackRoutes);
+  await app.register(reactionRoutes);
   await app.register(connectionRoutes);
   await app.register(deviceRoutes);
   await app.register(realtimeRoutes);