Easily Selectable History (#1672)

This update replaces the previous ratatui history widget with an
append-only log so that the terminal can handle text selection and
scrolling. It also disables streaming responses, which we'll do our best
to bring back in a later PR. It also adds a small summary of token use
after the TUI exits.

codex-rs/Cargo.lock

@@ -852,6 +852,7 @@ dependencies = [
  "tui-markdown",
  "tui-textarea",
  "unicode-segmentation",
+ "unicode-width 0.1.14",
  "uuid",
 ]