fix(cli): batch resize history replay

cli.py

@@ -1473,6 +1473,7 @@ def _replay_output_history() -> None:
         return
     _OUTPUT_HISTORY_REPLAYING = True
     try:
+        rendered_lines = []
         for entry in tuple(_OUTPUT_HISTORY):
             if callable(entry):
                 try:
@@ -1483,8 +1484,15 @@ def _replay_output_history() -> None:
                     lines = lines.splitlines()
             else:
                 lines = [entry]
-            for line in lines:
-                _pt_print(_PT_ANSI(str(line)))
+            rendered_lines.extend(str(line) for line in lines)
+        if rendered_lines:
+            # Replay after resize can contain hundreds of history lines. A
+            # per-line prompt_toolkit print forces one synchronous terminal I/O
+            # and redraw cycle per line, which users perceive as a waterfall of
+            # old output. Keep the existing history contents unchanged, but
+            # emit the replay as one ANSI payload so resize recovery does a
+            # single prompt_toolkit print/redraw.
+            _pt_print(_PT_ANSI("\n".join(rendered_lines)))
     except Exception:
         pass
     finally:

tests/cli/test_cprint_bg_thread.py

@@ -258,10 +258,25 @@ def test_replay_output_history_rerenders_callable_entries(monkeypatch):
     cli._replay_output_history()
 
     assert widths_seen == ["called"]
-    assert printed == ["top border", "body"]
+    assert printed == ["top border\nbody"]
     assert list(cli._OUTPUT_HISTORY) == [_render_current_width]
 
 
+def test_replay_output_history_batches_rendered_lines_into_one_print(monkeypatch):
+    cli._configure_output_history(True, 10)
+    cli._record_output_history("first line")
+    cli._record_output_history("second line")
+    cli._record_output_history_entry(lambda: ["third line", "fourth line"])
+    printed = []
+
+    monkeypatch.setattr(cli, "_pt_print", lambda value: printed.append(value))
+    monkeypatch.setattr(cli, "_PT_ANSI", lambda text: text)
+
+    cli._replay_output_history()
+
+    assert printed == ["first line\nsecond line\nthird line\nfourth line"]
+
+
 def test_suspend_output_history_blocks_recording():
     cli._configure_output_history(True, 10)