tui: coalesce command output; show unabridged commands in transcript (#2590)

https://github.com/user-attachments/assets/effec7c7-732a-4b61-a2ae-3cb297b6b19b

codex-rs/tui/src/streaming/mod.rs

@@ -64,6 +64,8 @@ impl HeaderEmitter {
 
     pub(crate) fn maybe_emit(&mut self, out_lines: &mut Vec<ratatui::text::Line<'static>>) -> bool {
         if !self.emitted_in_stream && !self.emitted_this_turn {
+            // Add a leading blank line before the header for visual spacing
+            out_lines.push(ratatui::text::Line::from(""));
             out_lines.push(render_header_line());
             self.emitted_in_stream = true;
             self.emitted_this_turn = true;