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/click/getMouseEventOptions.d.ts

@@ -0,0 +1,31 @@
+export declare function getMouseEventOptions(event: string, init?: MouseEventInit, clickCount?: number): {
+    detail: number;
+    buttons: number;
+    button: number;
+    clientX?: number | undefined;
+    clientY?: number | undefined;
+    movementX?: number | undefined;
+    movementY?: number | undefined;
+    relatedTarget?: EventTarget | null | undefined;
+    screenX?: number | undefined;
+    screenY?: number | undefined;
+    altKey?: boolean | undefined;
+    ctrlKey?: boolean | undefined;
+    metaKey?: boolean | undefined;
+    modifierAltGraph?: boolean | undefined;
+    modifierCapsLock?: boolean | undefined;
+    modifierFn?: boolean | undefined;
+    modifierFnLock?: boolean | undefined;
+    modifierHyper?: boolean | undefined;
+    modifierNumLock?: boolean | undefined;
+    modifierScrollLock?: boolean | undefined;
+    modifierSuper?: boolean | undefined;
+    modifierSymbol?: boolean | undefined;
+    modifierSymbolLock?: boolean | undefined;
+    shiftKey?: boolean | undefined;
+    view?: Window | null | undefined;
+    which?: number | undefined;
+    bubbles?: boolean | undefined;
+    cancelable?: boolean | undefined;
+    composed?: boolean | undefined;
+};