Pin Node 24 via .node-version/.nvmrc and pnpm 9.15.0 via
package.json#packageManager. Regenerate lockfile as pnpm-lock.yaml.
Rewrite README setup + scripts table around pnpm, and add a
production deployment guide covering systemd, nginx, upgrades,
rollback, and backups.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>