refactor: reorganize config order, clean up comments, restore xdg.configFile for nix-shell unfree support

home.nix

@@ -20,9 +20,6 @@
     gpu-screen-recorder-gtk
   ];
 
-  # 让 nix-shell 等传统命令也能安装 unfree 软件
-  xdg.configFile."nixpkgs/config.nix".text = "{ allowUnfree = true; }";
-
   # 用 Home Manager 固定 Fcitx5 输入法配置，仅保留拼音
   home.file.".config/fcitx5/profile".text = ''
     [Groups/0]
@@ -43,9 +40,12 @@
   '';
 
   home.sessionPath = [
-  "$HOME/.npm-global/bin"
+    "$HOME/.npm-global/bin"
   ];
 
+  # 让 nix-shell 等传统命令也能安装 unfree 软件
+  xdg.configFile."nixpkgs/config.nix".text = "{ allowUnfree = true; }";
+
   programs.bash = {
     enable = true;
     initExtra = ''