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/resolve-url-loader/lib/engine/fail-processing.js

@@ -0,0 +1,18 @@
+/*
+ * MIT License http://opensource.org/licenses/MIT
+ * Author: Ben Holloway @bholloway
+ */
+'use strict';
+
+/**
+ * Process the given CSS content into reworked CSS content.
+ */
+function process() {
+  return new Promise(function (_, reject) {
+    setTimeout(function () {
+      reject(new Error('This "engine" is designed to fail at processing time, for testing purposes only'));
+    }, 100);
+  });
+}
+
+module.exports = process;