Enable ChatGPT and restructure Codex module

- Set `chatgpt.enable = true` for both Garand‑Desktop and Garand‑Laptop.
- Rename `modules/home/codex.nix` to `modules/home/codex/default.nix`.
- Add `mutableSettings = true` and import `plugins.nix` in the Codex
  module.
- Introduce `modules/home/codex/plugins.nix` defining Codex plugins and
  marketplaces.
- Update `modules/home/default.nix` to import the new Codex directory.
- Refresh ChatGPT desktop entry icon SHA256 hash.

modules/home/codex/default.nix

@@ -9,9 +9,10 @@
   config.programs.codex = lib.mkIf config.codex.enable {
     enable = true;
     package = pkgs.codex;
-    # skills = {
-    #   ponytail = /home/${username}/.agents/skills/ponytail;
-    #   caveman = /home/${username}/.agents/skills/caveman;
-    # };
+    mutableSettings = true;
   };
+
+  imports = [
+    ./plugins.nix
+  ];
 }

modules/home/codex/plugins.nix

@@ -0,0 +1,48 @@
+{pkgs, ...}: let
+  ponytail = pkgs.fetchFromGitHub {
+    name = "ponytail";
+    owner = "DietrichGebert";
+    repo = "ponytail";
+    tag = "v5.3.2";
+    sha256 = "sha256-IJlhfkdXI6pMZZCZO7XBRg88LBiNfzc5Gnm4ofGybL8=";
+  };
+
+  context-mode = pkgs.fetchFromGitHub {
+    name = "context-mode";
+    owner = "mksglu";
+    repo = "context-mode";
+    tag = "v1.0.169";
+    sha256 = "sha256-1pV56ZB2aqod+C0kb5myuiWLAJ7+opiaurwZZ3BGKYk=";
+  };
+
+  understand-anything-src = pkgs.fetchFromGitHub {
+    name = "understand-anything";
+    owner = "Egonex-AI";
+    repo = "Understand-Anything";
+    tag = "v2.9.0";
+    sha256 = "sha256-nECfbp0vyFZRZX0Zg2s4ga/kYSCihJxYt9lxUHLGmFA=";
+  };
+
+  understand-anything =
+    pkgs.runCommand "understand-anything" {
+      version = "2.9.0";
+      nativeBuildInputs = [pkgs.jq];
+    } ''
+      mkdir -p "$out"
+      cp -r ${understand-anything-src}/understand-anything-plugin/. "$out/"
+      mkdir -p "$out/.codex-plugin"
+      jq '. + {skills: "./skills/", hooks: "./hooks/hooks.json"}' \
+        "$out/.claude-plugin/plugin.json" > "$out/.codex-plugin/plugin.json"
+      test -f "$out/skills/understand/SKILL.md"
+      test -f "$out/hooks/hooks.json"
+    '';
+in {
+  programs.codex = {
+    plugins = [ponytail understand-anything context-mode];
+    marketplaces = {
+      ponytail = ponytail;
+      Understand-Anything = understand-anything-src;
+      context-mode = context-mode;
+    };
+  };
+}

modules/home/default.nix

@@ -2,6 +2,7 @@ _: {
   imports = [
     ./bash
     ./chromium
+    ./codex
     ./fastfetch
     ./fish
     ./hyprland
@@ -19,7 +20,6 @@ _: {
     ./btop.nix
     ./cargo.nix
     ./cava.nix
-    ./codex.nix
     ./easyeffects.nix
     ./eza.nix
     ./fzf.nix

modules/home/xdg/desktop-entries.nix

@@ -46,7 +46,7 @@
       displayName = "ChatGPT";
       url = "https://chatgpt.com/";
       iconUrl = "https://static.vecteezy.com/system/resources/previews/031/110/149/large_2x/chatgpt-logo-transparent-free-png.png";
-      iconSha = "sha256-ZWmhchblQkksW02eduVrkUSPAlWPGC2fjqxrAGAF5jw=";
+      iconSha = "sha256-WXR/d28ynaBe+kZpnkUAaHcriDVSge98weS5Dza+AvQ=";
     }
     {
       name = "claude";