Improve mpv playback configuration

web/backend/src/server.ts

@@ -31,6 +31,12 @@ const app = express();
 app.use(express.json());
 expressWs(app);
 
+const frontendDistPath = [
+    path.join(__dirname, "../dist/frontend"),
+    path.join(__dirname, "../../frontend/dist"),
+].find((candidate) => fs.existsSync(path.join(candidate, "index.html")))
+    || path.join(__dirname, "../dist/frontend");
+
 const apiRouter = express.Router();
 const mediaPlayer = new MediaPlayer();
 
@@ -300,14 +306,14 @@ apiRouter.get("/features", withErrorHandling(async (req, res) => {
 }));
 
 // Serve static files for React app (after building)
-app.use(express.static(path.join(__dirname, "../dist/frontend")));
+app.use(express.static(frontendDistPath));
 
 // 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(path.join(__dirname, "../dist/frontend/index.html"));
+    res.sendFile(path.join(frontendDistPath, "index.html"));
 });
 
 const port = process.env.PORT || 3000;