Add react-doctor derivation

pkgs/react-doctor.nix

@@ -0,0 +1,23 @@
+{ lib, nodejs, pkgs, buildNpmPackage, fetchFromGitHub }:
+buildNpmPackage rec {
+  pname = "react-doctor";
+  version = "0.0.1";
+  
+  src = fetchFromGitHub {
+    owner = "millionco";
+    repo = "react-doctor";
+    rev = "v${version}";
+    hash = "sha256-T8szJcXeqIWmZQU/D4KpeFU1ZXilThL5JBmw2Y0hZkw=";
+  };
+  
+  npmDepsHash = lib.fakeSha256;
+  
+  npmBuild = "build";
+  
+  meta = with lib; {
+    description = "Let coding agents diagnose and fix your React code";
+    homepage = "https://github.com/millionco/react-doctor";
+    license = licenses.mit;
+    mainProgram = "react-doctor";
+  };
+}