feat: implement comprehensive admin dashboard for server management and user oversight

frontend/electron/services/backend.ts

@@ -119,4 +119,48 @@ export class BackendService {
       throw new Error(e.response?.data?.message || 'Failed to revoke all access');
     }
   }
+
+  // --- Admin API ---
+
+  public async getAdminStats() {
+    if (!this.token) return null;
+    try {
+      const response = await axios.get(`${this.url}/api/admin/stats`, { headers: this.headers });
+      return response.data;
+    } catch (e) { return null; }
+  }
+
+  public async getAdminUsers() {
+    if (!this.token) return [];
+    try {
+      const response = await axios.get(`${this.url}/api/admin/users`, { headers: this.headers });
+      return response.data;
+    } catch (e) { return []; }
+  }
+
+  public async deleteUser(userId: string) {
+    if (!this.token) return;
+    try {
+      await axios.delete(`${this.url}/api/admin/users/${userId}`, { headers: this.headers });
+    } catch (e: any) {
+      throw new Error(e.response?.data?.message || 'Failed to delete user');
+    }
+  }
+
+  public async getAdminAccounts() {
+    if (!this.token) return [];
+    try {
+      const response = await axios.get(`${this.url}/api/admin/accounts`, { headers: this.headers });
+      return response.data;
+    } catch (e) { return []; }
+  }
+
+  public async forceRemoveAccount(steamId: string) {
+    if (!this.token) return;
+    try {
+      await axios.delete(`${this.url}/api/admin/accounts/${steamId}`, { headers: this.headers });
+    } catch (e: any) {
+      throw new Error(e.response?.data?.message || 'Failed to remove account');
+    }
+  }
 }