feat(nixos): add phantom-ship host and streamline server installer ✨

- New host config: phantom-ship.nix (SSH, auto-rebuild, nix-ld, Ethernet)
- Hardware stub: phantom-ship-hardware.nix (replaced by install script)
- Add phantom-ship to flake.nix with home-manager
- Install script now auto-provisions post-install:
  - Clones dotfiles to /etc/dotfiles
  - Installs SSH public key (SSH_PUBKEY_FILE env var)
  - Generates hardware config
  - Supports INSTALLER_HOSTNAME and INSTALLER_DISK env vars
- Fix bootstrap-install.sh default branch to main
- Update CLAUDE.md and server-installer-usb.md

nixos/flake.nix

@@ -72,6 +72,26 @@
         ];
       };
 
+      phantom-ship = nixpkgs.lib.nixosSystem {
+        system = "x86_64-linux";
+        modules = [
+          ./hosts/phantom-ship.nix
+
+          # Home Manager on NixOS
+          home-manager.nixosModules.home-manager
+          ({ lib, ... }: {
+            home-manager.useGlobalPkgs = true;
+            home-manager.useUserPackages = true;
+            home-manager.backupFileExtension = "backup";
+            home-manager.users.danny = { ... }: {
+              home.username = "danny";
+              home.homeDirectory = lib.mkForce "/home/danny";
+              home.stateVersion = "25.11";
+            };
+          })
+        ];
+      };
+
       # For disko-install: LUKS + WiFi; hostname/WiFi via --system-config.
       server-install = nixpkgs.lib.nixosSystem {
         system = "x86_64-linux";