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/core-js-pure/actual/array/index.js

@@ -0,0 +1,16 @@
+'use strict';
+var parent = require('../../stable/array');
+require('../../modules/esnext.array.from-async');
+require('../../modules/esnext.array.group');
+require('../../modules/esnext.array.group-to-map');
+// TODO: Remove from `core-js@4`
+require('../../modules/esnext.array.find-last');
+require('../../modules/esnext.array.find-last-index');
+require('../../modules/esnext.array.group-by');
+require('../../modules/esnext.array.group-by-to-map');
+require('../../modules/esnext.array.to-reversed');
+require('../../modules/esnext.array.to-sorted');
+require('../../modules/esnext.array.to-spliced');
+require('../../modules/esnext.array.with');
+
+module.exports = parent;