- Add import-tree input; flake.nix now auto-loads every file under
./flake-modules so new hosts/features drop in without editing flake.nix.
- Extract the duplicated dotfiles-rebuild service, timer, and
safe.directory wiring into nixos/modules/dotfiles-rebuild.nix, exposed
via flake.nixosModules.dotfiles-rebuild.
- sunken-ship and phantom-ship now pull it in from their flake-modules;
hostname-specific flakeRef is derived from config.networking.hostName.