Require revocable authorization for automatic lobby removal

src/lib/autoscaling.ts

@@ -13,6 +13,7 @@ export interface ScalingMember {
     name: string; identity: string; state: 'occupied' | 'empty' | 'creating' | 'removing' | 'stopped' | 'unknown' | 'protected';
     players: number | null; observedAt: number | null; source: string | null;
     emptySince: number | null; blocker: string | null; operationId: string | null;
+    emptyStartedAt?: number | null;
 }
 export interface ScalingSnapshot {
     members: ScalingMember[]; reservedNames: string[]; keyedNames: string[]; blockers: string[];