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/eslint/lib/cli-engine/formatters/json-with-metadata.js

@@ -0,0 +1,16 @@
+/**
+ * @fileoverview JSON reporter, including rules metadata
+ * @author Chris Meyer
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Public Interface
+//------------------------------------------------------------------------------
+
+module.exports = function(results, data) {
+    return JSON.stringify({
+        results,
+        metadata: data
+    });
+};