Fix remaining any types and enable strict mode

src/hooks/useAdminGuard.ts

@@ -1,5 +1,6 @@
 import { useEffect } from 'react';
 import { useNavigate } from 'react-router-dom';
+import type { User } from '@supabase/supabase-js';
 import { useAuth } from './useAuth';
 import { useUserRole } from './useUserRole';
 import { useRequireMFA } from './useRequireMFA';
@@ -15,7 +16,7 @@ export interface AdminGuardState {
   needsMFA: boolean;
   
   /** Current authenticated user */
-  user: any;
+  user: User | null;
 }
 
 /**