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/_createInverter.js

@@ -0,0 +1,17 @@
+var baseInverter = require('./_baseInverter');
+
+/**
+ * Creates a function like `_.invertBy`.
+ *
+ * @private
+ * @param {Function} setter The function to set accumulator values.
+ * @param {Function} toIteratee The function to resolve iteratees.
+ * @returns {Function} Returns the new inverter function.
+ */
+function createInverter(setter, toIteratee) {
+  return function(object, iteratee) {
+    return baseInverter(object, setter, toIteratee(iteratee), {});
+  };
+}
+
+module.exports = createInverter;