chore(nix): use mkShellNoCC for lighter devShell

Switch from mkShell to mkShellNoCC since this development environment only uses Python and Node.js tools. The C compiler (stdenv) is not needed, resulting in fewer dependencies and faster shell activation.

Author: ryoppippi

flake.nix

@@ -89,7 +89,7 @@
             };
           };
 
-          devShells.default = pkgs.mkShell {
+          devShells.default = pkgs.mkShellNoCC {
             buildInputs = with pkgs; [
               uv
               just