fixed callback url

src/routes/callback/+layout.svelte

@@ -0,0 +1 @@
+<slot/>

src/routes/callback/+page.js

@@ -0,0 +1,20 @@
+import { Client } from '$lib/client/client.js';
+import { goto } from '$app/navigation';
+import { error } from '@sveltejs/kit';
+import { get } from 'svelte/store';
+
+export const ssr = false;
+
+export async function load({ params, url }) {
+    const client = get(Client.get());
+    let auth_code = url.searchParams.get("code");
+    if (auth_code) {
+        client.getToken(auth_code).then(() => {
+            client.save();
+            goto(url.origin);
+        });
+    }
+    error(400, {
+        message: "Bad request"
+    });
+}