Performance optimizations: Bundle size reduction

Optimizations implemented:
1. Font display: swap + preload for critical fonts
2. ReactQueryDevtools: Lazy load in dev only, exclude from production
3. Auth forms code splitting: LoginForm, PasswordResetRequestForm
4. Remove invalid swcMinify option (default in Next.js 15)

Results:
- Login page: 178 kB → 104 kB (74 kB saved, 42% reduction)
- Password reset: 178 kB → 104 kB (74 kB saved, 42% reduction)
- Homepage: 108 kB (baseline 102 kB shared + 6 kB page)

Remaining issue:
- 102 kB baseline shared by all pages (React Query + Auth loaded globally)

frontend/src/app/(auth)/login/page.tsx

@@ -1,6 +1,20 @@
 'use client';
 
-import { LoginForm } from '@/components/auth/LoginForm';
+import dynamic from 'next/dynamic';
+
+// Code-split LoginForm - heavy with react-hook-form + validation
+const LoginForm = dynamic(
+  () => import('@/components/auth/LoginForm').then((mod) => ({ default: mod.LoginForm })),
+  {
+    loading: () => (
+      <div className="space-y-4">
+        <div className="animate-pulse h-10 bg-muted rounded" />
+        <div className="animate-pulse h-10 bg-muted rounded" />
+        <div className="animate-pulse h-10 bg-primary/20 rounded" />
+      </div>
+    ),
+  }
+);
 
 export default function LoginPage() {
   return (