Add a TUI setting to disable automatic recaps (#42101)

## What changed

- Add the `tui.auto_recap` configuration option, enabled by default.
- When disabled, cancel scheduled automatic recap checks, reject automatic
  requests, and discard pending automatic results without retrying.
- Keep manual `/recap` requests available regardless of the setting.

## Testing

- Cover configuration defaults and command-line overrides.
- Cover scheduling cancellation, pending request cleanup, discarded results,
  and manual recaps while automatic recaps are disabled.

GitOrigin-RevId: 7d5323f58a2c84e60683a25a8c77653097efe6e2

codex-rs/thread-manager-sample/src/main.rs

@@ -224,6 +224,7 @@ fn new_config(model: Option<String>, arg0_paths: Arg0DispatchPaths) -> anyhow::R
         tui_notifications: TuiNotificationSettings::default(),
         animations: true,
         show_tooltips: true,
+        tui_auto_recap: true,
         model_availability_nux: ModelAvailabilityNuxConfig::default(),
         tui_alternate_screen: AltScreenMode::Auto,
         tui_status_line: None,