feat: usernames

also change userId to number

src/app/create-username/page.tsx

@@ -0,0 +1,22 @@
+import { auth } from "@/lib/auth";
+
+import UsernameForm from "../components/username-form";
+import { redirect } from "next/navigation";
+
+export default async function CreateUsernamePage() {
+	const session = await auth();
+
+	// If the user is not logged in or already has a username, redirect
+	if (!session || session?.user.username) {
+		redirect("/");
+	}
+
+	return (
+		<div>
+			<h1 className="text-3xl font-medium text-center">Welcome to TomodachiShare!</h1>
+			<h2 className="text-lg text-center">Please create a username</h2>
+
+			<UsernameForm />
+		</div>
+	);
+}