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/events/tests/legacy-compat.js

@@ -0,0 +1,16 @@
+// sigh... life is hard
+if (!global.console) {
+    console = {}
+}
+
+var fns = ['log', 'error', 'trace'];
+for (var i=0 ; i<fns.length ; ++i) {
+    var fn = fns[i];
+    if (!console[fn]) {
+        console[fn] = function() {};
+    }
+}
+
+if (!Array.isArray) {
+    Array.isArray = require('isarray');
+}