feat: redirect /[username] to /@[username] if no page matches

frontend/src/routes/[username]/+page.server.ts

@@ -0,0 +1,19 @@
+import { ErrorCode, type APIError, type User } from "$lib/api/entities";
+import { apiFetch } from "$lib/api/fetch";
+import { error, redirect } from "@sveltejs/kit";
+
+export const load = async ({ params }) => {
+  try {
+    const resp = await apiFetch<User>(`/users/${params.username}`, {
+      method: "GET",
+    });
+
+    throw redirect(303, `/@${resp.name}`);
+  } catch (e) {
+    if ((e as APIError).code === ErrorCode.UserNotFound) {
+      throw error(404, (e as APIError).message);
+    }
+
+    throw e;
+  }
+};

frontend/src/routes/[username]/+page.svelte

@@ -0,0 +1 @@
+<h1>Page not found</h1>