add admin toggle to user actions; update state management for admin status

src/app/admin/users/AdminUserActions.tsx

@@ -19,6 +19,7 @@ export function AdminUserActions({ user }: { user: UserData }) {
   const [balance, setBalance] = useState(String(user.balance))
   const [points, setPoints] = useState(String(user.researchPoints))
   const [hidden, setHidden] = useState(user.isHidden)
+  const [isAdmin, setIsAdmin] = useState(user.isAdmin)
   const [loading, setLoading] = useState(false)
   const [resetUrl, setResetUrl] = useState<string | null>(null)
   const [lotteryReset, setLotteryReset] = useState(false)
@@ -34,6 +35,7 @@ export function AdminUserActions({ user }: { user: UserData }) {
         balance: parseFloat(balance),
         researchPoints: parseInt(points, 10),
         isHidden: hidden,
+        isAdmin,
       }),
     })
     const data = await res.json()
@@ -133,6 +135,23 @@ export function AdminUserActions({ user }: { user: UserData }) {
                   }`} />
                 </button>
               </div>
+              <div className="flex items-center justify-between">
+                <div>
+                  <label className="text-sm text-slate-400">Admin</label>
+                  <p className="text-xs text-slate-500">Full access to the admin panel</p>
+                </div>
+                <button
+                  type="button"
+                  onClick={() => setIsAdmin((a) => !a)}
+                  className={`relative inline-flex h-6 w-11 items-center rounded-full transition-colors ${
+                    isAdmin ? 'bg-amber-500' : 'bg-slate-600'
+                  }`}
+                >
+                  <span className={`inline-block h-4 w-4 transform rounded-full bg-white transition-transform ${
+                    isAdmin ? 'translate-x-6' : 'translate-x-1'
+                  }`} />
+                </button>
+              </div>
             </div>
 
             {error && (