Gatus is configured entirely via YAML (mapped from Nix attrsets),
making nix-config the single source of truth for all monitoring
config instead of Uptime Kuma's web UI/SQLite database.
- Add incus.nix module for fully declarative Incus/LXC containers
- Build NixOS LXC images using nixpkgs.lib.nixosSystem
- Ephemeral containers: recreated on each start, cleaned up on stop
- Use flock to serialize concurrent container operations
- Deterministic MAC addresses via lib.mkMac to prevent ARP cache issues
- Add veth* to NetworkManager unmanaged interfaces
- Update CLAUDE.md with coding conventions and shared lib docs
