fix: unique key prefix to avoid React duplicate key warning

src/app/admin/bookings/page.tsx

@@ -837,7 +837,7 @@ function BookingsPageInner() {
           </div>
 
           {/* Tab content — auto-refreshes when new bookings detected */}
-          <div className="mt-4" key={refreshKey}>
+          <div className="mt-4" key={`tab-${refreshKey}`}>
             {tab === "reminders" && <RemindersTab />}
             {tab === "classes" && <GroupBookingsTab filter={statusFilter} />}
             {tab === "master-classes" && <McRegistrationsTab filter={statusFilter} />}