Drop stale backend-era comment from wav export. The Python backend and
backend/ directory were already removed; no further stub files remain.
Co-authored-by: Cursor <cursoragent@cursor.com>
Replace hidden file inputs and anchor downloads with native open/save
dialogs via a thin platform layer. WAV export sends base64 audio data to
the Go backend for writing to the user-chosen path.
Co-authored-by: Cursor <cursoragent@cursor.com>
end