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/routes/safety.ts

@@ -10,6 +10,7 @@ import { requireUser } from '../lib/auth';
 import { HttpError } from '../lib/http';
 import { FOLLOWS_CHANGED_CHANNEL, redis } from '../lib/redis';
 import { toUserSummary } from '../services/nowPlaying';
+import { removeReactionsBetween } from './reactions';
 
 async function findUser(username: string) {
   const [user] = await db.select().from(schema.users).where(eq(schema.users.username, username.toLowerCase()));
@@ -46,6 +47,7 @@ export async function safetyRoutes(app: FastifyInstance) {
           ),
         );
     });
+    await removeReactionsBetween(me.id, them.id);
     await followsChanged(me.id, them.id);
     return { ok: true };
   });