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/@testing-library/user-event/dist/utils/misc/hasPointerEvents.d.ts

@@ -0,0 +1,15 @@
+/**
+ * Options that can be passed to any event that relies
+ * on pointer-events property
+ */
+export declare interface PointerOptions {
+    /**
+     * When set to `true` the event skips checking if any element
+     * in the DOM-tree has `'pointer-events: none'` set. This check is
+     * costly in general  and very costly when rendering large DOM-trees.
+     * Can be used to speed up tests.
+     * Default: `false`
+     * */
+    skipPointerEventsCheck?: boolean;
+}
+export declare function hasPointerEvents(element: Element): boolean;