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/tui/Cargo.toml

@@ -58,6 +58,7 @@ tui-input = "0.14.0"
 tui-markdown = "0.3.3"
 tui-textarea = "0.7.0"
 unicode-segmentation = "1.12.0"
+unicode-width = "0.1"
 uuid = "1"
 
 [dev-dependencies]