Dockerize the proxy (all-in-one image) + Docker docs

All-in-one Dockerfile bundling OpenResty + the Node mgmt app + Redis in one
container, mirroring the bare-metal ops/install.sh layout:
- Dockerfile (openresty/openresty:1.31.1.1-2-bookworm-fat base; dumb-init PID 1;
  luarocks install lua-resty-auto-ssl/luasocket/lua-resty-ipmatcher; node 22.x;
  npm ci --omit=dev; OpenResty confs + lua copied into place).
- docker-entrypoint.sh: fallback cert, sed-parameterize RESOLVER/REAL_IP_FROM,
  start bundled redis + node app, exec openresty foreground.
- docker-compose.yml (standalone), .dockerignore, DEPLOYMENT.md.
- nodejs/routes/render.js: /health endpoint for healthchecks.
- nodejs/models/user_ldap.js: tlsOptions forwarded to ldapts Client so the
  proxy can bind ldaps:// with a self-signed cert (app_ldap__tlsOptions__*).
- nodejs/package.json: bump @simpleworkjs/conf to ^1.1.0 (app_* env overrides).
- docs/docker.md + index.md: Docker deployment guide + fronting an SSO Manager.
- ops/proxy.service: add WorkingDirectory=/var/www/proxy/nodejs (bare-metal
  cwd fix so relative conf/ paths resolve).

Co-Authored-By: Claude <noreply@anthropic.com>

nodejs/package.json

@@ -22,7 +22,7 @@
   "dependencies": {
     "@fortawesome/fontawesome-free": "^7.3.0",
     "@popperjs/core": "^2.11.8",
-    "@simpleworkjs/conf": "^1.0.0",
+    "@simpleworkjs/conf": "^1.1.0",
     "acme-client": "^5.4.0",
     "axios": "^1.13.5",
     "bcrypt": "^6.0.0",