Add sent-message history to the chat composer

[hamzamerzic]

Summary

• add Up/Down keyboard history for visible owner-authored chat messages
• preserve the unfinished draft when moving into and back out of history
• defer to native textarea navigation for wrapped lines, selections, modifier chords, and IME composition
• keep hidden file-session details out of recalled text and rebase live dictation before recall changes the draft

Testing

• npm test (1,866 tests passed)
• npm run build
• verified in Chromium that ArrowUp moves through wrapped visual lines, recalls only after the visual top, and then stops at the oldest entry