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/status/tests.rs

@@ -1525,6 +1525,42 @@ async fn status_snapshot_truncates_in_narrow_terminal() {
     assert_snapshot!(sanitized);
 }
 
+#[tokio::test]
+async fn status_snapshot_truncates_halfwidth_kana_in_narrow_terminal() {
+    let temp_home = TempDir::new().expect("temp home");
+    let mut config = test_config(&temp_home).await;
+    set_workspace_cwd(&mut config, test_path_buf("/workspace/tests").abs());
+
+    let account = StatusAccountDisplay::ChatGpt {
+        email: Some("ｶﾞﾊﾟｶﾞﾊﾟｶﾞﾊﾟ@example.com".to_string()),
+        plan: Some("ｶﾞﾊﾟ plan".to_string()),
+    };
+    let usage = TokenUsage::default();
+    let now = chrono::Local
+        .with_ymd_and_hms(2024, 1, 2, 3, 4, 5)
+        .single()
+        .expect("timestamp");
+    let composite = new_status_output(
+        &config,
+        Some(&account),
+        /*token_info*/ None,
+        &usage,
+        &None,
+        Some("ｶﾞﾊﾟｶﾞﾊﾟｶﾞﾊﾟｶﾞﾊﾟ thread".to_string()),
+        /*forked_from*/ None,
+        /*rate_limits*/ None,
+        /*plan_type*/ None,
+        now,
+        "ｶﾞﾊﾟｶﾞﾊﾟｶﾞﾊﾟｶﾞﾊﾟ-model",
+        Some("ｶﾞﾊﾟ collaboration mode"),
+        /*reasoning_effort_override*/ None,
+    );
+    let rendered_lines = render_lines(&composite.display_lines(/*width*/ 42));
+    let sanitized = sanitize_directory(rendered_lines).join("\n");
+
+    assert_snapshot!(sanitized);
+}
+
 #[tokio::test]
 async fn status_snapshot_shows_missing_limits_message() {
     let temp_home = TempDir::new().expect("temp home");