Unsent draft text lost when switching sessions (VS Code extension)

Unsent draft text in the input box is lost when switching between sessions (VS Code extension, macOS). I typed a long message, switched to another session to copy a few lines, switched back — the input box was empty and the text was gone for good. No recovery, since unsent input is never persisted.

This is a known issue (#34596 closed as "not planned", also #55578, #2743), but the cost is real — I lost ~30 minutes of work.

Request: retain the draft per-session in memory (at least while the app is open) so returning to a session restores the text. Ideally persist to disk like transcripts. At minimum, warn before discarding unsaved input.