fix: Wrap useSearchParams in Suspense boundary

Next.js 15 requires useSearchParams() to be wrapped in a
Suspense boundary for static page generation.

- Split LoginForm into separate component
- Add Suspense wrapper with loading skeleton
- Fixes build error on /login page

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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

@@ -1,6 +1,6 @@
 'use client'
 
-import { useState } from 'react'
+import { Suspense, useState } from 'react'
 import { useRouter, useSearchParams } from 'next/navigation'
 import { signIn } from 'next-auth/react'
 import { Button } from '@/components/ui/button'
@@ -15,7 +15,7 @@ import {
   CardTitle,
 } from '@/components/ui/card'
 
-export default function LoginPage() {
+function LoginForm() {
   const router = useRouter()
   const searchParams = useSearchParams()
   const callbackUrl = searchParams.get('callbackUrl') || '/'
@@ -55,7 +55,6 @@ export default function LoginPage() {
   }
 
   return (
-    <div className="min-h-screen flex items-center justify-center bg-gray-50 py-12 px-4 sm:px-6 lg:px-8">
     <Card className="w-full max-w-md">
       <CardHeader className="space-y-1">
         <CardTitle className="text-2xl font-bold text-center">
@@ -128,6 +127,35 @@ export default function LoginPage() {
         </CardFooter>
       </form>
     </Card>
+  )
+}
+
+function LoginFormSkeleton() {
+  return (
+    <Card className="w-full max-w-md">
+      <CardHeader className="space-y-1">
+        <CardTitle className="text-2xl font-bold text-center">
+          LetsBe Hub
+        </CardTitle>
+        <CardDescription className="text-center">
+          Loading...
+        </CardDescription>
+      </CardHeader>
+      <CardContent className="space-y-4">
+        <div className="h-10 bg-gray-200 rounded animate-pulse" />
+        <div className="h-10 bg-gray-200 rounded animate-pulse" />
+        <div className="h-10 bg-gray-200 rounded animate-pulse" />
+      </CardContent>
+    </Card>
+  )
+}
+
+export default function LoginPage() {
+  return (
+    <div className="min-h-screen flex items-center justify-center bg-gray-50 py-12 px-4 sm:px-6 lg:px-8">
+      <Suspense fallback={<LoginFormSkeleton />}>
+        <LoginForm />
+      </Suspense>
     </div>
   )
 }