Instead of trying to replay a truncated byte buffer through pyte, this
change maintains a pyte Screen object within TerminalSession that gets
updated as terminal data flows through. This provides accurate terminal
state for screenshots without issues from buffer truncation.
Key changes:
- Add pyte Screen and Stream to TerminalSession
- Update screen state as data arrives via _update_screen()
- Add get_screen_lines() to return current screen state
- Resize pyte screen when terminal size changes
- Update local_server to use get_screen_lines() directly
- Remove _apply_carriage_returns() workaround
This properly fixes the tmux status bar 'creeping up' issue by ensuring
the screenshot always reflects the actual terminal state.