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/get.js

@@ -0,0 +1,11 @@
+var superPropBase = require("./superPropBase.js");
+function _get() {
+  return module.exports = _get = "undefined" != typeof Reflect && Reflect.get ? Reflect.get.bind() : function (e, t, r) {
+    var p = superPropBase(e, t);
+    if (p) {
+      var n = Object.getOwnPropertyDescriptor(p, t);
+      return n.get ? n.get.call(arguments.length < 3 ? e : r) : n.value;
+    }
+  }, module.exports.__esModule = true, module.exports["default"] = module.exports, _get.apply(null, arguments);
+}
+module.exports = _get, module.exports.__esModule = true, module.exports["default"] = module.exports;