xint-versioned-install-layout-pattern

xint follows the VPS infra versioned installation pattern: /opt/infra/xint/releases/<version>/ for each release, /opt/infra/xint/current/ symlink pointing to active release, /opt/infra/xint/data/ for persistent runtime data (outside releases), /opt/infra/xint/.env (chmod 600) for credentials, and /usr/local/bin/xint global launcher. Upgrades only require pointing the current symlink to the new release; the data/ symlink preserves all accumulated metrics.