Stage 4a of the dendritic + clan migration. Both servers now live under
clan.machines (via nixos/flake-modules/clan.nix) and clan-core generates
their nixosConfigurations for us; the previous per-host flake-modules
are removed.
Notes:
- clan.core.enableRecommendedDefaults = false on both machines so we
keep the existing dhcpcd / non-networkd / non-resolved stack. Services
like dnsmasq, navidrome, and the existing wireless setup break with
the clan defaults on.
- dotfiles-rebuild timer is untouched (safety net). Replacing it with
clan machines update / dm-pull-deploy comes in 4e.
- mac stays outside the clan as admin only.
Verified: `clan machines list --flake path:…/nixos` returns both hosts;
both servers rebuild cleanly and all services (navidrome, cloudflare-
tunnel, fitness-bot, dnsmasq, openclaw-gateway, sshd) stay active.
