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/_baseMean.js

@@ -0,0 +1,20 @@
+var baseSum = require('./_baseSum');
+
+/** Used as references for various `Number` constants. */
+var NAN = 0 / 0;
+
+/**
+ * The base implementation of `_.mean` and `_.meanBy` without support for
+ * iteratee shorthands.
+ *
+ * @private
+ * @param {Array} array The array to iterate over.
+ * @param {Function} iteratee The function invoked per iteration.
+ * @returns {number} Returns the mean.
+ */
+function baseMean(array, iteratee) {
+  var length = array == null ? 0 : array.length;
+  return length ? (baseSum(array, iteratee) / length) : NAN;
+}
+
+module.exports = baseMean;