fix(tui): clean up pending steer preview wrapping (#13642)

## Summary
- render pending steer previews with a single `pending steer:` prefix
instead of repeating it for each source line
- reuse the same truncation path for pending steers and queued drafts so
multiline previews behave consistently
- add snapshot coverage for the multiline pending steer case

Before
<img width="969" height="219" alt="Screenshot 2026-03-05 at 3 55 11 PM"
src="https://github.com/user-attachments/assets/b062c9c8-43d3-4a52-98e0-3c7643d1697b"
/>

After
<img width="965" height="203" alt="Screenshot 2026-03-05 at 3 56 08 PM"
src="https://github.com/user-attachments/assets/40935863-55b3-444f-9e14-1ac63126b2e1"
/>

## Codex author
`codex resume 019cc054-385e-79a3-bb85-ec9499623bd8`

Co-authored-by: Codex <noreply@openai.com>

codex-rs/tui/src/bottom_pane/pending_input_preview.rs

@@ -25,6 +25,8 @@ pub(crate) struct PendingInputPreview {
     edit_binding: key_hint::KeyBinding,
 }
 
+const PREVIEW_LINE_LIMIT: usize = 3;
+
 impl PendingInputPreview {
     pub(crate) fn new() -> Self {
         Self {
@@ -41,6 +43,18 @@ impl PendingInputPreview {
         self.edit_binding = binding;
     }
 
+    fn push_truncated_preview_lines(
+        lines: &mut Vec<Line<'static>>,
+        wrapped: Vec<Line<'static>>,
+        overflow_line: Line<'static>,
+    ) {
+        let wrapped_len = wrapped.len();
+        lines.extend(wrapped.into_iter().take(PREVIEW_LINE_LIMIT));
+        if wrapped_len > PREVIEW_LINE_LIMIT {
+            lines.push(overflow_line);
+        }
+    }
+
     fn as_renderable(&self, width: u16) -> Box<dyn Renderable> {
         if (self.pending_steers.is_empty() && self.queued_messages.is_empty()) || width < 4 {
             return Box::new(());
@@ -50,36 +64,26 @@ impl PendingInputPreview {
 
         for steer in &self.pending_steers {
             let wrapped = adaptive_wrap_lines(
-                steer
-                    .lines()
-                    .map(|line| format!("pending steer: {line}").dim()),
+                steer.lines().map(|line| Line::from(line.dim())),
                 RtOptions::new(width as usize)
-                    .initial_indent(Line::from("  ! ".dim()))
+                    .initial_indent(Line::from("  ! pending steer: ".dim()))
                     .subsequent_indent(Line::from("    ")),
             );
-            let len = wrapped.len();
-            for line in wrapped.into_iter().take(3) {
-                lines.push(line);
-            }
-            if len > 3 {
-                lines.push(Line::from("    …".dim()));
-            }
+            Self::push_truncated_preview_lines(&mut lines, wrapped, Line::from("    …".dim()));
         }
 
         for message in &self.queued_messages {
             let wrapped = adaptive_wrap_lines(
-                message.lines().map(|line| line.dim().italic()),
+                message.lines().map(|line| Line::from(line.dim().italic())),
                 RtOptions::new(width as usize)
                     .initial_indent(Line::from("  ↳ ".dim()))
                     .subsequent_indent(Line::from("    ")),
             );
-            let len = wrapped.len();
-            for line in wrapped.into_iter().take(3) {
-                lines.push(line);
-            }
-            if len > 3 {
-                lines.push(Line::from("    …".dim().italic()));
-            }
+            Self::push_truncated_preview_lines(
+                &mut lines,
+                wrapped,
+                Line::from("    …".dim().italic()),
+            );
         }
 
         if !self.queued_messages.is_empty() {
@@ -266,4 +270,20 @@ mod tests {
             format!("{buf:?}")
         );
     }
+
+    #[test]
+    fn render_multiline_pending_steer_uses_single_prefix_and_truncates() {
+        let mut queue = PendingInputPreview::new();
+        queue
+            .pending_steers
+            .push("First line\nSecond line\nThird line\nFourth line".to_string());
+        let width = 48;
+        let height = queue.desired_height(width);
+        let mut buf = Buffer::empty(Rect::new(0, 0, width, height));
+        queue.render(Rect::new(0, 0, width, height), &mut buf);
+        assert_snapshot!(
+            "render_multiline_pending_steer_uses_single_prefix_and_truncates",
+            format!("{buf:?}")
+        );
+    }
 }

codex-rs/tui/src/bottom_pane/snapshots/codex_tui__bottom_pane__pending_input_preview__tests__render_multiline_pending_steer_uses_single_prefix_and_truncates.snap

@@ -0,0 +1,23 @@
+---
+source: tui/src/bottom_pane/pending_input_preview.rs
+expression: "format!(\"{buf:?}\")"
+---
+Buffer {
+    area: Rect { x: 0, y: 0, width: 48, height: 4 },
+    content: [
+        "  ! pending steer: First line                   ",
+        "    Second line                                 ",
+        "    Third line                                  ",
+        "    …                                           ",
+    ],
+    styles: [
+        x: 0, y: 0, fg: Reset, bg: Reset, underline: Reset, modifier: DIM,
+        x: 29, y: 0, fg: Reset, bg: Reset, underline: Reset, modifier: NONE,
+        x: 4, y: 1, fg: Reset, bg: Reset, underline: Reset, modifier: DIM,
+        x: 15, y: 1, fg: Reset, bg: Reset, underline: Reset, modifier: NONE,
+        x: 4, y: 2, fg: Reset, bg: Reset, underline: Reset, modifier: DIM,
+        x: 14, y: 2, fg: Reset, bg: Reset, underline: Reset, modifier: NONE,
+        x: 0, y: 3, fg: Reset, bg: Reset, underline: Reset, modifier: DIM,
+        x: 5, y: 3, fg: Reset, bg: Reset, underline: Reset, modifier: NONE,
+    ]
+}