refactor: migrate auth pages to better-auth client

src/app/auth/signin/page.tsx

@@ -1,15 +1,35 @@
-import { signIn, auth } from "@/auth"
+"use client"
+
+import { signIn, useSession } from "@/lib/auth-client"
 import { Button } from "@/components/ui/button"
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card"
-import { redirect } from "next/navigation"
 import Link from "next/link"
+import { useRouter } from "next/navigation"
+import { useEffect } from "react"
 
-export default async function SignInPage() {
-  const session = await auth()
+export default function SignInPage() {
+  const { data: session, isPending } = useSession()
+  const router = useRouter()
+
+  useEffect(() => {
+    if (session?.user) {
+      router.push("/")
+    }
+  }, [session, router])
+
+  const handleSignIn = async () => {
+    await signIn.social({
+      provider: "authentik",
+      callbackURL: "/",
+    })
+  }
+
+  if (isPending) {
+    return null
+  }
 
-  // If already signed in, redirect to home
   if (session?.user) {
-    redirect("/")
+    return null
   }
 
   return (
@@ -22,16 +42,9 @@ export default async function SignInPage() {
           </CardDescription>
         </CardHeader>
         <CardContent className="space-y-4">
-          <form
-            action={async () => {
-              "use server"
-              await signIn("authentik", { redirectTo: "/" })
-            }}
-          >
-            <Button type="submit" className="w-full" size="lg">
-              Continue with Authentik
-            </Button>
-          </form>
+          <Button onClick={handleSignIn} className="w-full" size="lg">
+            Continue with Authentik
+          </Button>
 
           <div className="text-center">
             <Link href="/" className="text-sm text-muted-foreground hover:underline">