Add floating dev/debug menu for QA testing (Ctrl+D)

Four-tab panel with resource manipulation, time controls, state inspection,
and event triggers to accelerate testing across all game systems.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/hooks/useKeyboardShortcuts.ts

@@ -5,6 +5,12 @@ import type { GameSpeed } from '@ai-tycoon/shared';
 export function useKeyboardShortcuts() {
   useEffect(() => {
     const handler = (e: KeyboardEvent) => {
+      if (e.ctrlKey && e.key === 'd') {
+        e.preventDefault();
+        window.dispatchEvent(new Event('toggle-dev-menu'));
+        return;
+      }
+
       const target = e.target as HTMLElement;
       if (target.tagName === 'INPUT' || target.tagName === 'TEXTAREA' || target.tagName === 'SELECT') return;