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/async/internal/wrapAsync.js

@@ -0,0 +1,34 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+exports.isAsyncIterable = exports.isAsyncGenerator = exports.isAsync = undefined;
+
+var _asyncify = require('../asyncify.js');
+
+var _asyncify2 = _interopRequireDefault(_asyncify);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+function isAsync(fn) {
+    return fn[Symbol.toStringTag] === 'AsyncFunction';
+}
+
+function isAsyncGenerator(fn) {
+    return fn[Symbol.toStringTag] === 'AsyncGenerator';
+}
+
+function isAsyncIterable(obj) {
+    return typeof obj[Symbol.asyncIterator] === 'function';
+}
+
+function wrapAsync(asyncFn) {
+    if (typeof asyncFn !== 'function') throw new Error('expected a function');
+    return isAsync(asyncFn) ? (0, _asyncify2.default)(asyncFn) : asyncFn;
+}
+
+exports.default = wrapAsync;
+exports.isAsync = isAsync;
+exports.isAsyncGenerator = isAsyncGenerator;
+exports.isAsyncIterable = isAsyncIterable;