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/lz-string/typings/lz-string.d.ts

@@ -0,0 +1,14 @@
+export function compressToBase64(input: string): string;
+export function decompressFromBase64(input: string): string;
+
+export function compressToUTF16(input: string): string;
+export function decompressFromUTF16(compressed: string): string;
+
+export function compressToUint8Array(uncompressed: string): Uint8Array;
+export function decompressFromUint8Array(compressed: Uint8Array): string;
+
+export function compressToEncodedURIComponent(input: string): string;
+export function decompressFromEncodedURIComponent(compressed: string): string;
+
+export function compress(input: string): string;
+export function decompress(compressed: string): string;