Switch from RabbitMQ to server-sent events

(not fully working yet)

backend/lib/rabbit.ts

@@ -63,7 +63,7 @@ export class RabbitMQ {
                 this.timeouts.delete(phone.id);
                 phone.active = false;
                 await phone.save();
-            }, 30_000);
+            }, 60_000);
             this.timeouts.set(phone.id, timeoutTimer);
             
             this.publish(phone.user.toString(), newBeat.toJSON(), 'beat');