Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/@babel/runtime/helpers/esm/objectWithoutPropertiesLoose.js

@@ -0,0 +1,10 @@
+function _objectWithoutPropertiesLoose(r, e) {
+  if (null == r) return {};
+  var t = {};
+  for (var n in r) if ({}.hasOwnProperty.call(r, n)) {
+    if (-1 !== e.indexOf(n)) continue;
+    t[n] = r[n];
+  }
+  return t;
+}
+export { _objectWithoutPropertiesLoose as default };