Fix TUI layout for halfwidth Japanese sound marks (#35962)

## What changed

- Use Ratatui-compatible terminal widths throughout TUI layout, preserving
  full-width counters for long lines.
- Wrap and truncate on grapheme boundaries so halfwidth kana sound marks and
  emoji sequences stay intact.
- Apply the corrected sizing to text input, selection popups, status and
  history cells, Markdown, hyperlinks, and scrollable cloud diffs.

## Testing

- Add focused unit and snapshot coverage for wrapping, truncation, cursor and
  mask alignment, popup columns, status output, session headers, Markdown
  tables, process output, and scrollable diffs.

GitOrigin-RevId: 294ec0bcff743c6bb16d55ec26308524ce741879

codex-rs/tui/src/markdown_render.rs

@@ -49,6 +49,8 @@ use crate::terminal_hyperlinks::annotate_web_urls_in_line;
 use crate::terminal_hyperlinks::remap_wrapped_line;
 use crate::terminal_hyperlinks::visible_lines;
 use crate::terminal_hyperlinks::web_destination;
+use crate::width::char_width;
+use crate::width::display_width;
 use crate::wrapping::RtOptions;
 use crate::wrapping::adaptive_wrap_line;
 use crate::wrapping::word_wrap_line;
@@ -72,8 +74,6 @@ use std::ops::Range;
 use std::path::Path;
 use std::path::PathBuf;
 use std::sync::LazyLock;
-use unicode_width::UnicodeWidthChar;
-use unicode_width::UnicodeWidthStr;
 use url::Url;
 
 mod streaming;
@@ -1302,7 +1302,7 @@ where
                 let plain = cell.plain_text();
                 let mut word_count = 0usize;
                 for token in plain.split_whitespace() {
-                    let token_width = token.width();
+                    let token_width = display_width(token);
                     body_token_width = body_token_width.max(token_width);
                     long_body_token_count += usize::from(token_width >= 20);
                     word_count += 1;
@@ -1311,7 +1311,7 @@ where
                     body_token_count += word_count;
                     total_words += word_count;
                     total_cells += 1;
-                    total_cell_width += plain.width();
+                    total_cell_width += display_width(&plain);
                 }
             }
 
@@ -1321,7 +1321,7 @@ where
                 total_words as f64 / total_cells as f64
             };
             let avg_cell_width = if total_cells == 0 {
-                header_plain.width() as f64
+                display_width(&header_plain) as f64
             } else {
                 total_cell_width as f64 / total_cells as f64
             };
@@ -1607,7 +1607,7 @@ where
                     } else {
                         current_text.push(ch);
                     }
-                    column += UnicodeWidthChar::width(ch).unwrap_or(/*default*/ 0);
+                    column += char_width(ch);
                 }
                 flush(&mut out, &mut current_text, current_destination);
             }
@@ -1756,7 +1756,10 @@ where
 
     #[inline]
     fn spans_display_width(spans: &[Span<'_>]) -> usize {
-        spans.iter().map(|span| span.content.width()).sum()
+        spans
+            .iter()
+            .map(|span| display_width(span.content.as_ref()))
+            .sum()
     }
 
     #[inline]
@@ -1775,7 +1778,10 @@ where
 
     #[inline]
     fn longest_token_width(text: &str) -> usize {
-        text.split_whitespace().map(str::width).max().unwrap_or(0)
+        text.split_whitespace()
+            .map(display_width)
+            .max()
+            .unwrap_or(0)
     }
 
     fn push_inline_style(&mut self, style: Style) {
@@ -1887,7 +1893,7 @@ where
                 }
             } else {
                 let mut spans = self.current_initial_indent.clone();
-                let shift = spans.iter().map(|span| span.content.width()).sum::<usize>();
+                let shift = Self::spans_display_width(&spans);
                 spans.append(&mut line.line.spans);
                 for hyperlink in &mut line.hyperlinks {
                     hyperlink.columns =
@@ -1926,7 +1932,7 @@ where
         };
 
         let mut spans = self.prefix_spans(pending_marker_line);
-        let shift = spans.iter().map(|span| span.content.width()).sum::<usize>();
+        let shift = Self::spans_display_width(&spans);
         spans.append(&mut line.line.spans);
         for hyperlink in &mut line.hyperlinks {
             hyperlink.columns = hyperlink.columns.start + shift..hyperlink.columns.end + shift;
@@ -2844,6 +2850,13 @@ mod tests {
         }));
     }
 
+    #[test]
+    fn table_widths_count_halfwidth_sound_marks() {
+        let cell = make_cell("ｶﾞﾊﾟ");
+        assert_eq!(W::cell_display_width(&cell), 4);
+        assert_eq!(W::longest_token_width("ｶﾞﾊﾟtail"), 8);
+    }
+
     #[test]
     fn key_value_table_keeps_web_annotations() {
         let destination = "https://example.com/a/very/long/path";