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/core-js-pure/internals/function-uncurry-this.js

@@ -0,0 +1,13 @@
+'use strict';
+var NATIVE_BIND = require('../internals/function-bind-native');
+
+var FunctionPrototype = Function.prototype;
+var call = FunctionPrototype.call;
+// eslint-disable-next-line es/no-function-prototype-bind -- safe
+var uncurryThisWithBind = NATIVE_BIND && FunctionPrototype.bind.bind(call, call);
+
+module.exports = NATIVE_BIND ? uncurryThisWithBind : function (fn) {
+  return function () {
+    return call.apply(fn, arguments);
+  };
+};