flake: remove disfunctional devShell

The shell alias looks dubious and the shellHook also doesn't work:

bash: /nix/store/b010ibix7i333qhv5smcb129yly1dmfj-cargo-setup-hook.sh:
Is a directory

This devShell is actually not needed. nix develop will just fallback to
the package, which has already all dependencies.
on the upside we can now use just callPackage which also work better
with cross-compilation than the current approach.

Author: Mic92

codex-rs/default.nix

@@ -1,41 +1,31 @@
-{ pkgs, ... }:
-let
+{
+  openssl,
+  rustPlatform,
+  pkg-config,
+  lib,
+  ...
+}:
+rustPlatform.buildRustPackage (finalAttrs: {
   env = {
-    PKG_CONFIG_PATH = "${pkgs.openssl.dev}/lib/pkgconfig:$PKG_CONFIG_PATH";
+    PKG_CONFIG_PATH = "${openssl.dev}/lib/pkgconfig:$PKG_CONFIG_PATH";
   };
-in
-rec {
-  package = pkgs.rustPlatform.buildRustPackage {
-    inherit env;
-    pname = "codex-rs";
-    version = "0.1.0";
-    cargoLock.lockFile = ./Cargo.lock;
-    doCheck = false;
-    src = ./.;
-    nativeBuildInputs = with pkgs; [
-      pkg-config
-      openssl
-    ];
-    cargoLock.outputHashes = {
-      "ratatui-0.29.0" = "sha256-HBvT5c8GsiCxMffNjJGLmHnvG77A6cqEL+1ARurBXho=";
-    };
-    meta = with pkgs.lib; {
-      description = "OpenAI Codex command‑line interface rust implementation";
-      license = licenses.asl20;
-      homepage = "https://github.com/openai/codex";
-    };
+  pname = "codex-rs";
+  version = "0.1.0";
+  cargoLock.lockFile = ./Cargo.lock;
+  doCheck = false;
+  src = ./.;
+  nativeBuildInputs = [
+    pkg-config
+    openssl
+  ];
+
+  cargoLock.outputHashes = {
+    "ratatui-0.29.0" = "sha256-HBvT5c8GsiCxMffNjJGLmHnvG77A6cqEL+1ARurBXho=";
   };
-  devShell = pkgs.mkShell {
-    inherit env;
-    name = "codex-rs-dev";
-    packages = [
-      pkgs.cargo
-      package
-    ];
-    shellHook = ''
-      echo "Entering development shell for codex-rs"
-      alias codex="cd ${package.src}/tui; cargo run; cd -"
-      ${pkgs.rustPlatform.cargoSetupHook}
-    '';
+
+  meta = with lib; {
+    description = "OpenAI Codex command‑line interface rust implementation";
+    license = licenses.asl20;
+    homepage = "https://github.com/openai/codex";
   };
-}
+})

flake.nix

@@ -20,19 +20,8 @@
           codex-rs = pkgs.callPackage ./codex-rs { };
         in
         {
-          codex-rs = codex-rs.package;
-          default = codex-rs.package;
-        }
-      );
-
-      devShells = forAllSystems (system:
-        let
-          pkgs = nixpkgs.legacyPackages.${system};
-          codex-rs = pkgs.callPackage ./codex-rs { };
-        in
-        {
-          codex-rs = codex-rs.devShell;
-          default = codex-rs.devShell;
+          codex-rs = codex-rs;
+          default = codex-rs;
         }
       );
     };