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/_copyArray.js

@@ -0,0 +1,20 @@
+/**
+ * Copies the values of `source` to `array`.
+ *
+ * @private
+ * @param {Array} source The array to copy values from.
+ * @param {Array} [array=[]] The array to copy values to.
+ * @returns {Array} Returns `array`.
+ */
+function copyArray(source, array) {
+  var index = -1,
+      length = source.length;
+
+  array || (array = Array(length));
+  while (++index < length) {
+    array[index] = source[index];
+  }
+  return array;
+}
+
+module.exports = copyArray;