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>

src/locales/en/translation.json

@@ -857,6 +857,30 @@
     "replace": "Replace",
     "replaceAll": "Replace All",
     "downloadInstead": "Download Instead",
+    "keyboardShortcuts": "Keyboard Shortcuts",
+    "searchAndReplace": "Search & Replace",
+    "editing": "Editing",
+    "navigation": "Navigation",
+    "code": "Code",
+    "search": "Search",
+    "findNext": "Find Next",
+    "findPrevious": "Find Previous",
+    "save": "Save",
+    "selectAll": "Select All",
+    "undo": "Undo",
+    "redo": "Redo",
+    "goToLine": "Go to Line",
+    "moveLineUp": "Move Line Up",
+    "moveLineDown": "Move Line Down",
+    "toggleComment": "Toggle Comment",
+    "indent": "Indent",
+    "outdent": "Outdent",
+    "autoComplete": "Auto Complete",
+    "imageLoadError": "Failed to load image",
+    "zoomIn": "Zoom In",
+    "zoomOut": "Zoom Out",
+    "rotate": "Rotate",
+    "originalSize": "Original Size",
     "startTyping": "Start typing...",
     "unknownSize": "Unknown size",
     "fileIsEmpty": "File is empty",