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/lodash/keysIn.js

@@ -0,0 +1,32 @@
+var arrayLikeKeys = require('./_arrayLikeKeys'),
+    baseKeysIn = require('./_baseKeysIn'),
+    isArrayLike = require('./isArrayLike');
+
+/**
+ * Creates an array of the own and inherited enumerable property names of `object`.
+ *
+ * **Note:** Non-object values are coerced to objects.
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category Object
+ * @param {Object} object The object to query.
+ * @returns {Array} Returns the array of property names.
+ * @example
+ *
+ * function Foo() {
+ *   this.a = 1;
+ *   this.b = 2;
+ * }
+ *
+ * Foo.prototype.c = 3;
+ *
+ * _.keysIn(new Foo);
+ * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
+ */
+function keysIn(object) {
+  return isArrayLike(object) ? arrayLikeKeys(object, true) : baseKeysIn(object);
+}
+
+module.exports = keysIn;