[tui] add optional details to TUI status header (#8293)

### What

Add optional `details` field to TUI's status indicator header. `details`
is shown under the header with text wrapping and a max height of 3
lines.

Duplicated changes to `tui2`.

### Why

Groundwork for displaying error details under `Reconnecting...` for
clarity with retryable errors.

Basic examples
<img width="1012" height="326" alt="image"
src="https://github.com/user-attachments/assets/dd751ceb-b179-4fb2-8fd1-e4784d6366fb"
/>

<img width="1526" height="358" alt="image"
src="https://github.com/user-attachments/assets/bbe466fc-faff-4a78-af7f-3073ccdd8e34"
/>

Truncation example
<img width="936" height="189" alt="image"
src="https://github.com/user-attachments/assets/f3f1b5dd-9050-438b-bb07-bd833c03e889"
/>

### Tests
Tested locally, added tests for truncation.

codex-rs/tui/src/chatwidget/tests.rs

@@ -3292,6 +3292,7 @@ async fn stream_recovery_restores_previous_status_header() {
         .status_widget()
         .expect("status indicator should be visible");
     assert_eq!(status.header(), "Working");
+    assert_eq!(status.details(), None);
     assert!(chat.retry_status_header.is_none());
 }