Support resumable game folder uploads and remove DLC declarations

src/routes/api/game-files/[id]/upload/+server.ts

@@ -0,0 +1,8 @@
+import { json } from '@sveltejs/kit';
+import { browserUploadStatus } from '$lib/server/game-files/index.js';
+import { gameFileError } from '$lib/server/game-files/http.js';
+
+export async function GET({ params }: { params: { id: string } }) {
+    try { return json(await browserUploadStatus(params.id), { headers: { 'Cache-Control': 'no-store' } }); }
+    catch (cause) { return gameFileError(cause); }
+}