Add Node.js server skeleton with auth, persistence, and admin console (custom-node-server branch)

src/admin.js

@@ -0,0 +1,50 @@
+const express = require('express');
+const basicAuth = require('basic-auth');
+const logger = require('./logger');
+
+let serverInstance;
+
+function ensureAuth(req, res, next) {
+  if (!process.env.ADMIN_USER || !process.env.ADMIN_PASS) return next();
+  const user = basicAuth(req);
+  if (!user || user.name !== process.env.ADMIN_USER || user.pass !== process.env.ADMIN_PASS) {
+    res.set('WWW-Authenticate', 'Basic realm="HeliumRecAdmin"');
+    return res.status(401).send('Authentication required');
+  }
+  return next();
+}
+
+function start({ port = 5056, getConnections }) {
+  const app = express();
+  app.use(express.json());
+
+  app.get('/health', (req, res) => res.json({ ok: true }));
+
+  app.use(ensureAuth);
+
+  app.get('/connections', (req, res) => {
+    const conns = [];
+    const map = getConnections();
+    map.forEach((v, k) => {
+      conns.push({ id: k, user: v.user, connectedAt: v.connectedAt, remote: v.ws?._meta?.remote });
+    });
+    res.json(conns);
+  });
+
+  app.post('/broadcast', (req, res) => {
+    const { message } = req.body || {};
+    if (!message) return res.status(400).json({ error: 'message required' });
+    const map = getConnections();
+    let sent = 0;
+    map.forEach((v) => {
+      try { v.ws.send(typeof message === 'string' ? message : JSON.stringify(message)); sent++; } catch (e) { logger.warn('broadcast failed', e.message); }
+    });
+    res.json({ sent });
+  });
+
+  serverInstance = app.listen(port, () => logger.info(`Admin console listening on http://0.0.0.0:${port}`));
+}
+
+function stop() { if (serverInstance) serverInstance.close(); }
+
+module.exports = { start, stop };