Switch production deployment from Docker to PM2 on Ubuntu.

Add Express gateway, ecosystem config, and one-click install with native PostgreSQL, Node, and Python venv on port 23566.

Co-authored-by: Cursor <cursoragent@cursor.com>

deploy/pm2/server.js

@@ -0,0 +1,31 @@
+const path = require('path')
+const fs = require('fs')
+const express = require('express')
+const { createProxyMiddleware } = require('http-proxy-middleware')
+
+const envPath = path.join(__dirname, '../../.env')
+if (fs.existsSync(envPath)) {
+  require('dotenv').config({ path: envPath })
+}
+
+const PORT = Number(process.env.WEB_PORT || 23566)
+const API_TARGET = process.env.API_TARGET || 'http://127.0.0.1:8000'
+const STATIC_ROOT = path.join(__dirname, '../../frontend/dist')
+
+const app = express()
+app.use(
+  '/api',
+  createProxyMiddleware({
+    target: API_TARGET,
+    changeOrigin: true,
+  }),
+)
+app.use(express.static(STATIC_ROOT, { maxAge: '1h', index: false }))
+app.get(/^\/(?!api).*/, (_req, res) => {
+  res.sendFile(path.join(STATIC_ROOT, 'index.html'))
+})
+
+app.listen(PORT, '0.0.0.0', () => {
+  console.log(`Grade archive web gateway listening on http://0.0.0.0:${PORT}`)
+  console.log(`API proxy target: ${API_TARGET}`)
+})