add nix flakes

backend/src/server.ts

@@ -1,5 +1,6 @@
 import express from "express";
 import expressWs from "express-ws";
+import path from "path";
 import { MediaPlayer } from "./MediaPlayer";
 import { searchInvidious, fetchThumbnail } from "./InvidiousAPI";
 import { PlaylistItem } from './types';
@@ -158,14 +159,14 @@ apiRouter.delete("/favorites", withErrorHandling(async (req, res) => {
 }));
 
 // Serve static files for React app (after building)
-app.use(express.static("dist/frontend"));
+app.use(express.static(path.join(__dirname, "../dist/frontend")));
 
 // Mount API routes under /api
 app.use("/api", apiRouter);
 
 // Serve React app for all other routes (client-side routing)
 app.get("*", (req, res) => {
-    res.sendFile("dist/frontend/index.html", { root: "." });
+    res.sendFile(path.join(__dirname, "../dist/frontend/index.html"));
 });
 
 const port = process.env.PORT || 3000;