AI Implementation feature(871): Admin Area System: Database Backup/Restore and Danger Zone (#61)

frontend/src/app/core/services/auth.service.ts

@@ -240,6 +240,17 @@ export class AuthService {
     this.publishInvalidation(message);
   }
 
+  /**
+   * Forcibly invalidate the local session (and broadcast peer
+   * invalidation) — used after a destructive server-initiated action such
+   * as a successful restore that revokes access. Same as a normal logout
+   * from the client's perspective.
+   */
+  forceServerInvalidation(): void {
+    this.suppressBroadcast = false;
+    this.clearAndBroadcast();
+  }
+
   handleSseUnauthorized(): void {
     this.clearAndBroadcast();
     this.notifyPeerInvalidation('sse-unauthorized');

frontend/src/app/core/services/system-data-change.service.ts

@@ -0,0 +1,14 @@
+import { Injectable, signal } from '@angular/core';
+
+export type SystemDataChangeKind = 'scores-reset' | 'challenges-wiped' | 'restore-completed';
+
+@Injectable({ providedIn: 'root' })
+export class SystemDataChangeService {
+  private readonly _events = signal<{ kind: SystemDataChangeKind; ts: number }[]>([]);
+
+  readonly events = this._events.asReadonly();
+
+  notify(kind: SystemDataChangeKind): void {
+    this._events.update((cur) => [...cur, { kind, ts: Date.now() }]);
+  }
+}