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/regexp-exec-abstract.js

@@ -0,0 +1,21 @@
+'use strict';
+var call = require('../internals/function-call');
+var anObject = require('../internals/an-object');
+var isCallable = require('../internals/is-callable');
+var classof = require('../internals/classof-raw');
+var regexpExec = require('../internals/regexp-exec');
+
+var $TypeError = TypeError;
+
+// `RegExpExec` abstract operation
+// https://tc39.es/ecma262/#sec-regexpexec
+module.exports = function (R, S) {
+  var exec = R.exec;
+  if (isCallable(exec)) {
+    var result = call(exec, R, S);
+    if (result !== null) anObject(result);
+    return result;
+  }
+  if (classof(R) === 'RegExp') return call(regexpExec, R, S);
+  throw new $TypeError('RegExp#exec called on incompatible receiver');
+};