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.
Adds a DocBlock component that renders embedded documents, new export buttons for DOCX
and PDF, and updates the file‑upload picker to accept *.txt, *.docx, *.pptx, and *.pdf.
Introduces a DOCX→PDF conversion bridge in the backend and new /tts and /asr
endpoints that expose TTS and speech‑recognition functionality. The README is
rewritten to describe the new features and clean up legacy documentation. All
changes are backward‑compatible and do not introduce breaking API changes.
ydy0615