feat: helix - add steel as the plugin system

fix: evaluation warning - 'system' has been renamed to/replaced by 'stdenv.hostPlatform.system'

Signed-off-by: Ryan Yin <xiaoyin_c@qq.com>

home/base/core/editors/helix/default.nix

@@ -1,6 +1,4 @@
 { pkgs, ... }:
 {
-  programs.helix = {
-    enable = true;
-  };
+  programs.helix.enable = true;
 }

home/base/gui/terminal/ghostty.nix

@@ -16,7 +16,7 @@
         pkgs.hello # pkgs.ghostty is currently broken on darwin
       else
         pkgs.ghostty; # the stable version
-    # package = ghostty.packages.${pkgs.system}.default; # the latest version
+    # package = ghostty.packages.${pkgs.stdenv.hostPlatform.system}.default; # the latest version
     enableBashIntegration = false;
     installBatSyntax = false;
     # installVimSyntax = true;

home/base/tui/editors/helix/default.nix

@@ -1,8 +1,20 @@
-{ pkgs, ... }:
+{ pkgs, helix, ... }:
+
+let
+  helixPackages = helix.packages.${pkgs.stdenv.hostPlatform.system};
+in
 {
+  home.packages = with pkgs; [
+    steel
+  ];
+
   programs.helix = {
     enable = true;
-    package = pkgs.helix;
+    # https://github.com/helix-editor/helix/pull/8675
+    package = helixPackages.default.overrideAttrs (prevAttrs: {
+      # enable steel as the plugin system
+      cargoBuildFeatures = prevAttrs.cargoBuildFeatures or [ ] ++ [ "steel" ];
+    });
     settings = {
       editor = {
         line-number = "relative";