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/eslint-plugin-jsx-a11y/lib/util/isDOMElement.js

@@ -0,0 +1,15 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports["default"] = void 0;
+var _ariaQuery = require("aria-query");
+/**
+ * Returns boolean indicating whether the given element is a DOM element.
+ */
+var isDOMElement = function isDOMElement(tagName) {
+  return _ariaQuery.dom.has(tagName);
+};
+var _default = exports["default"] = isDOMElement;
+module.exports = exports.default;