Introduce ContextMenu.vue and FileContent.vue components for interactive file operations
and file preview.
Update FileTree to support root drop, integrate the new components into DocsView,
and refresh i18n strings for file actions.
Refactor MilkdownEditor to embed TTS menu and player.
Add a file tree UI and corresponding composable for local file management.
Introduce TTS menu and player components for voice synthesis integration.
Add new EditorView and DocsView routes and update SettingsPanel view switching.
Enhance Mermaid plugin with improved styling and action buttons.
ydy0615