refactor: Use haumea for filesystem-based module system for flake outputs

refactor: Use hyphen(`-`) for variable names & folder names(except Python), replace all unserscore(`_`) with hyphen(`-`).

outputs/x86_64-linux/src/idols-ruby.nix

@@ -0,0 +1,45 @@
+{
+  # NOTE: the args not used in this file CAN NOT be removed!
+  # because haumea pass argument lazily,
+  # and these arguments are used in the functions like `mylib.nixosSystem`, `mylib.colmenaSystem`, etc.
+  inputs,
+  lib,
+  mylib,
+  myvars,
+  system,
+  genSpecialArgs,
+  ...
+} @ args: let
+  # 星野 瑠美衣, Hoshino Rubii
+  name = "ruby";
+  tags = [name "homelab-operation"];
+  ssh-user = "root";
+
+  modules = {
+    nixos-modules =
+      (map mylib.relativeToRoot [
+        # common
+        "secrets/nixos.nix"
+        "modules/nixos/server/server.nix"
+        "modules/nixos/server/proxmox-hardware-configuration.nix"
+        # host specific
+        "hosts/idols-${name}"
+      ])
+      ++ [
+        {modules.secrets.server.operation.enable = true;}
+      ];
+    home-modules.imports = map mylib.relativeToRoot [
+      "home/linux/server.nix"
+    ];
+  };
+
+  systemArgs = modules // args;
+in {
+  nixosConfigurations.${name} = mylib.nixosSystem systemArgs;
+
+  colmena.${name} =
+    mylib.colmenaSystem (systemArgs // {inherit tags ssh-user;});
+
+  # generate proxmox image for virtual machines without desktop environment
+  packages.${name} = inputs.self.nixosConfigurations.${name}.config.formats.proxmox;
+}