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/_createRange.js

@@ -0,0 +1,30 @@
+var baseRange = require('./_baseRange'),
+    isIterateeCall = require('./_isIterateeCall'),
+    toFinite = require('./toFinite');
+
+/**
+ * Creates a `_.range` or `_.rangeRight` function.
+ *
+ * @private
+ * @param {boolean} [fromRight] Specify iterating from right to left.
+ * @returns {Function} Returns the new range function.
+ */
+function createRange(fromRight) {
+  return function(start, end, step) {
+    if (step && typeof step != 'number' && isIterateeCall(start, end, step)) {
+      end = step = undefined;
+    }
+    // Ensure the sign of `-0` is preserved.
+    start = toFinite(start);
+    if (end === undefined) {
+      end = start;
+      start = 0;
+    } else {
+      end = toFinite(end);
+    }
+    step = step === undefined ? (start < end ? 1 : -1) : toFinite(step);
+    return baseRange(start, end, step, fromRight);
+  };
+}
+
+module.exports = createRange;