[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/status_indicator_widget.rs

@@ -10,7 +10,11 @@ use ratatui::buffer::Buffer;
 use ratatui::layout::Rect;
 use ratatui::style::Stylize;
 use ratatui::text::Line;
+use ratatui::text::Span;
+use ratatui::text::Text;
+use ratatui::widgets::Paragraph;
 use ratatui::widgets::WidgetRef;
+use unicode_width::UnicodeWidthStr;
 
 use crate::app_event::AppEvent;
 use crate::app_event_sender::AppEventSender;
@@ -18,11 +22,18 @@ use crate::exec_cell::spinner;
 use crate::key_hint;
 use crate::render::renderable::Renderable;
 use crate::shimmer::shimmer_spans;
+use crate::text_formatting::capitalize_first;
 use crate::tui::FrameRequester;
+use crate::wrapping::RtOptions;
+use crate::wrapping::word_wrap_lines;
+
+const DETAILS_MAX_LINES: usize = 3;
+const DETAILS_PREFIX: &str = "  └ ";
 
 pub(crate) struct StatusIndicatorWidget {
     /// Animated header text (defaults to "Working").
     header: String,
+    details: Option<String>,
     show_interrupt_hint: bool,
 
     elapsed_running: Duration,
@@ -58,6 +69,7 @@ impl StatusIndicatorWidget {
     ) -> Self {
         Self {
             header: String::from("Working"),
+            details: None,
             show_interrupt_hint: true,
             elapsed_running: Duration::ZERO,
             last_resume_at: Instant::now(),
@@ -78,11 +90,23 @@ impl StatusIndicatorWidget {
         self.header = header;
     }
 
+    /// Update the details text shown below the header.
+    pub(crate) fn update_details(&mut self, details: Option<String>) {
+        self.details = details
+            .filter(|details| !details.is_empty())
+            .map(|details| capitalize_first(details.trim_start()));
+    }
+
     #[cfg(test)]
     pub(crate) fn header(&self) -> &str {
         &self.header
     }
 
+    #[cfg(test)]
+    pub(crate) fn details(&self) -> Option<&str> {
+        self.details.as_deref()
+    }
+
     pub(crate) fn set_interrupt_hint_visible(&mut self, visible: bool) {
         self.show_interrupt_hint = visible;
     }
@@ -132,11 +156,43 @@ impl StatusIndicatorWidget {
     pub fn elapsed_seconds(&self) -> u64 {
         self.elapsed_seconds_at(Instant::now())
     }
+
+    /// Wrap the details text into a fixed width and return the lines, truncating if necessary.
+    fn wrapped_details_lines(&self, width: u16) -> Vec<Line<'static>> {
+        let Some(details) = self.details.as_deref() else {
+            return Vec::new();
+        };
+        if width == 0 {
+            return Vec::new();
+        }
+
+        let prefix_width = UnicodeWidthStr::width(DETAILS_PREFIX);
+        let opts = RtOptions::new(usize::from(width))
+            .initial_indent(Line::from(DETAILS_PREFIX.dim()))
+            .subsequent_indent(Line::from(Span::from(" ".repeat(prefix_width)).dim()))
+            .break_words(true);
+
+        let mut out = word_wrap_lines(details.lines().map(|line| vec![line.dim()]), opts);
+
+        if out.len() > DETAILS_MAX_LINES {
+            out.truncate(DETAILS_MAX_LINES);
+            let content_width = usize::from(width).saturating_sub(prefix_width).max(1);
+            let max_base_len = content_width.saturating_sub(1);
+            if let Some(last) = out.last_mut()
+                && let Some(span) = last.spans.last_mut()
+            {
+                let trimmed: String = span.content.as_ref().chars().take(max_base_len).collect();
+                *span = format!("{trimmed}…").dim();
+            }
+        }
+
+        out
+    }
 }
 
 impl Renderable for StatusIndicatorWidget {
-    fn desired_height(&self, _width: u16) -> u16 {
-        1
+    fn desired_height(&self, width: u16) -> u16 {
+        1 + u16::try_from(self.wrapped_details_lines(width).len()).unwrap_or(0)
     }
 
     fn render(&self, area: Rect, buf: &mut Buffer) {
@@ -170,7 +226,16 @@ impl Renderable for StatusIndicatorWidget {
             spans.push(format!("({pretty_elapsed})").dim());
         }
 
-        Line::from(spans).render_ref(area, buf);
+        let mut lines = Vec::new();
+        lines.push(Line::from(spans));
+        if area.height > 1 {
+            // If there is enough space, add the details lines below the header.
+            let details = self.wrapped_details_lines(area.width);
+            let max_details = usize::from(area.height.saturating_sub(1));
+            lines.extend(details.into_iter().take(max_details));
+        }
+
+        Paragraph::new(Text::from(lines)).render_ref(area, buf);
     }
 }
 
@@ -229,6 +294,27 @@ mod tests {
         insta::assert_snapshot!(terminal.backend());
     }
 
+    #[test]
+    fn renders_wrapped_details_panama_two_lines() {
+        let (tx_raw, _rx) = unbounded_channel::<AppEvent>();
+        let tx = AppEventSender::new(tx_raw);
+        let mut w = StatusIndicatorWidget::new(tx, crate::tui::FrameRequester::test_dummy(), false);
+        w.update_details(Some("A man a plan a canal panama".to_string()));
+        w.set_interrupt_hint_visible(false);
+
+        // Freeze time-dependent rendering (elapsed + spinner) to keep the snapshot stable.
+        w.is_paused = true;
+        w.elapsed_running = Duration::ZERO;
+
+        // Prefix is 4 columns, so a width of 30 yields a content width of 26: one column
+        // short of fitting the whole phrase (27 cols), forcing exactly one wrap without ellipsis.
+        let mut terminal = Terminal::new(TestBackend::new(30, 3)).expect("terminal");
+        terminal
+            .draw(|f| w.render(f.area(), f.buffer_mut()))
+            .expect("draw");
+        insta::assert_snapshot!(terminal.backend());
+    }
+
     #[test]
     fn timer_pauses_when_requested() {
         let (tx_raw, _rx) = unbounded_channel::<AppEvent>();
@@ -250,4 +336,20 @@ mod tests {
         let after_resume = widget.elapsed_seconds_at(baseline + Duration::from_secs(13));
         assert_eq!(after_resume, before_pause + 3);
     }
+
+    #[test]
+    fn details_overflow_adds_ellipsis() {
+        let (tx_raw, _rx) = unbounded_channel::<AppEvent>();
+        let tx = AppEventSender::new(tx_raw);
+        let mut w = StatusIndicatorWidget::new(tx, crate::tui::FrameRequester::test_dummy(), true);
+        w.update_details(Some("abcd abcd abcd abcd".to_string()));
+
+        let lines = w.wrapped_details_lines(6);
+        assert_eq!(lines.len(), DETAILS_MAX_LINES);
+        let last = lines.last().expect("expected last details line");
+        assert!(
+            last.spans[1].content.as_ref().ends_with("…"),
+            "expected ellipsis in last line: {last:?}"
+        );
+    }
 }