feat(opsserver-access): add admin user listing to the access dashboard

ts/opsserver/handlers/admin.handler.ts

@@ -52,6 +52,18 @@ export class AdminHandler {
       role: 'admin',
     });
   }
+
+  /**
+   * Return a safe projection of the users Map — excludes password fields.
+   * Used by UsersHandler to serve the admin-only listUsers endpoint.
+   */
+  public listUsers(): Array<{ id: string; username: string; role: string }> {
+    return Array.from(this.users.values()).map((user) => ({
+      id: user.id,
+      username: user.username,
+      role: user.role,
+    }));
+  }
   
   private registerHandlers(): void {
     // Admin Login Handler