FIX: Resolve keyboard shortcuts and enhance image preview with i18n support

- Fix keyboard shortcut conflicts in FileViewer.tsx (Ctrl+F, H, ?, Space, A)
- Add comprehensive i18n translations for keyboard shortcuts help panel
- Integrate react-photo-view for enhanced fullscreen image viewing
- Simplify image preview by removing complex toolbar and hover hints
- Add proper error handling and loading states for image display
- Update English and Chinese translation files with new keyboard shortcut terms

🤖 Generated with [Claude Code](https://claude.ai/code)

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

package.json

@@ -93,6 +93,7 @@
     "react-hook-form": "^7.60.0",
     "react-i18next": "^15.7.3",
     "react-icons": "^5.5.0",
+    "react-photo-view": "^1.2.7",
     "react-resizable-panels": "^3.0.3",
     "react-simple-keyboard": "^3.8.120",
     "react-xtermjs": "^1.0.10",