feat(nix): add codex desktop launcher

nixos/code.nix

@@ -10,6 +10,7 @@ makeEnable config "myModules.code" true {
     antigravity
     claude-code
     codex
+    codex-desktop
     gemini-cli
     happy-coder
     opencode

nixos/flake.nix

@@ -205,6 +205,14 @@
       };
     };
 
+    codex-desktop-linux = {
+      url = "github:ilysenko/codex-desktop-linux";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+      };
+    };
+
     claude-code-nix = {
       url = "github:sadjow/claude-code-nix";
       inputs = {

nixos/nix.nix

@@ -111,6 +111,28 @@
         # Use codex and claude-code from dedicated flakes with cachix
         (final: prev: {
           codex = inputs.codex-cli-nix.packages.${prev.stdenv.hostPlatform.system}.default;
+          codex-desktop-installer = inputs.codex-desktop-linux.packages.${prev.stdenv.hostPlatform.system}.default;
+          codex-desktop = final.writeShellApplication {
+            name = "codex-desktop";
+            runtimeInputs = [
+              final.codex
+              final.codex-desktop-installer
+              final.coreutils
+              final.python3
+            ];
+            text = ''
+              install_root="''${CODEX_DESKTOP_HOME:-''${XDG_DATA_HOME:-$HOME/.local/share}/codex-desktop-linux}"
+              install_dir="''${CODEX_INSTALL_DIR:-$install_root/codex-app}"
+
+              if [ ! -x "$install_dir/start.sh" ]; then
+                mkdir -p "$install_root"
+                CODEX_INSTALL_DIR="$install_dir" codex-desktop-installer
+              fi
+
+              export CODEX_CLI_PATH="''${CODEX_CLI_PATH:-$(command -v codex)}"
+              exec "$install_dir/start.sh" "$@"
+            '';
+          };
           claude-code = inputs.claude-code-nix.packages.${prev.stdenv.hostPlatform.system}.default;
           git-sync-rs = inputs.git-sync-rs.packages.${prev.stdenv.hostPlatform.system}.default;
         })