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/src/slash_command.rs

@@ -15,7 +15,6 @@ pub enum SlashCommand {
     New,
     Diff,
     Quit,
-    ToggleMouseMode,
 }
 
 impl SlashCommand {
@@ -23,9 +22,6 @@ impl SlashCommand {
     pub fn description(self) -> &'static str {
         match self {
             SlashCommand::New => "Start a new chat.",
-            SlashCommand::ToggleMouseMode => {
-                "Toggle mouse mode (enable for scrolling, disable for text selection)"
-            }
             SlashCommand::Quit => "Exit the application.",
             SlashCommand::Diff => {
                 "Show git diff of the working directory (including untracked files)"