feat: add OS detection hook and integrate into FileBrowserDialog for improved keyboard shortcut handling

- Introduced useOSDetection hook to determine the user's operating system.
- Updated FileBrowserDialog to utilize the OS detection for displaying the correct keyboard shortcut (⌘ or Ctrl) based on the detected OS.

apps/ui/src/hooks/index.ts

@@ -3,6 +3,7 @@ export { useBoardBackgroundSettings } from './use-board-background-settings';
 export { useElectronAgent } from './use-electron-agent';
 export { useKeyboardShortcuts } from './use-keyboard-shortcuts';
 export { useMessageQueue } from './use-message-queue';
+export { useOSDetection, type OperatingSystem, type OSDetectionResult } from './use-os-detection';
 export { useResponsiveKanban } from './use-responsive-kanban';
 export { useScrollTracking } from './use-scroll-tracking';
 export { useSettingsMigration } from './use-settings-migration';