Add YouTube Music now-playing server, OBS overlay, and browser extension

Node.js server on port 9095 receives now-playing data via POST and broadcasts
to connected WebSocket clients. Includes a Firefox/Chrome extension that scrapes
YouTube Music's player bar every 3s, an OBS-ready transparent overlay with
animated equalizer bars, and an image proxy to bypass CDN restrictions in OBS.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/index.js

@@ -0,0 +1,98 @@
+const express = require('express');
+const http = require('http');
+const path = require('path');
+const { WebSocketServer } = require('ws');
+
+const app = express();
+const server = http.createServer(app);
+const wss = new WebSocketServer({ server });
+
+const PORT = 9095;
+
+// Current now-playing state
+let currentState = {
+  title: '',
+  artist: '',
+  album: '',
+  albumArt: '',
+  isPlaying: false,
+  progress: 0,
+  duration: 0,
+};
+
+// CORS middleware
+app.use((req, res, next) => {
+  res.header('Access-Control-Allow-Origin', '*');
+  res.header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
+  res.header('Access-Control-Allow-Headers', 'Content-Type');
+  if (req.method === 'OPTIONS') {
+    return res.sendStatus(204);
+  }
+  next();
+});
+
+// Parse JSON bodies
+app.use(express.json());
+
+// Serve static files from the overlay directory
+app.use(express.static(path.join(__dirname, '..', 'overlay')));
+
+// Image proxy — fetches album art server-side so OBS can display it
+app.get('/api/image-proxy', async (req, res) => {
+  const url = req.query.url;
+  if (!url) return res.status(400).send('Missing url parameter');
+  try {
+    const response = await fetch(url);
+    if (!response.ok) return res.status(response.status).send('Upstream error');
+    res.set('Content-Type', response.headers.get('content-type') || 'image/jpeg');
+    res.set('Cache-Control', 'public, max-age=3600');
+    const buffer = await response.arrayBuffer();
+    res.send(Buffer.from(buffer));
+  } catch (err) {
+    res.status(502).send('Failed to fetch image');
+  }
+});
+
+// Health check
+app.get('/api/health', (req, res) => {
+  res.json({ status: 'ok' });
+});
+
+// Get current now-playing state
+app.get('/api/now-playing', (req, res) => {
+  res.json(currentState);
+});
+
+// Update now-playing state
+app.post('/api/now-playing', (req, res) => {
+  const { title, artist, album, albumArt, isPlaying, progress, duration } = req.body;
+
+  currentState = {
+    title: title ?? currentState.title,
+    artist: artist ?? currentState.artist,
+    album: album ?? currentState.album,
+    albumArt: albumArt ?? currentState.albumArt,
+    isPlaying: isPlaying ?? currentState.isPlaying,
+    progress: progress ?? currentState.progress,
+    duration: duration ?? currentState.duration,
+  };
+
+  // Broadcast to all connected WebSocket clients
+  const message = JSON.stringify(currentState);
+  wss.clients.forEach((client) => {
+    if (client.readyState === 1) { // WebSocket.OPEN
+      client.send(message);
+    }
+  });
+
+  res.json(currentState);
+});
+
+// Send current state to newly connected WebSocket clients
+wss.on('connection', (ws) => {
+  ws.send(JSON.stringify(currentState));
+});
+
+server.listen(PORT, () => {
+  console.log(`Server running on http://localhost:${PORT}`);
+});