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/memfs/lib/Dirent.d.ts

@@ -0,0 +1,19 @@
+import { Link } from './node';
+import { TEncodingExtended, TDataOut } from './encoding';
+/**
+ * A directory entry, like `fs.Dirent`.
+ */
+export declare class Dirent {
+    static build(link: Link, encoding: TEncodingExtended | undefined): Dirent;
+    name: TDataOut;
+    private mode;
+    private _checkModeProperty;
+    isDirectory(): boolean;
+    isFile(): boolean;
+    isBlockDevice(): boolean;
+    isCharacterDevice(): boolean;
+    isSymbolicLink(): boolean;
+    isFIFO(): boolean;
+    isSocket(): boolean;
+}
+export default Dirent;