Adds operational resilience tooling:
- resilience/health-check.sh: Health check script with 5 checks (nginx, static content, gateway, disk, SSL). Supports --auto-restart and --verbose modes.
- resilience/service-restart.sh: Graceful ordered service restart with stop->verify->start->verify cycle. Supports --force mode.
- Fallback logic for when gateway is unreachable (graceful degradation to static pages)
All scripts are self-contained, no external dependencies, work on common Linux distros.