fix(cli): preserve renderer state on resize

tests/cli/test_cli_status_bar.py

@@ -3,6 +3,7 @@ from datetime import datetime, timedelta
 from types import SimpleNamespace
 from unittest.mock import MagicMock, patch
 
+import cli as cli_mod
 from cli import HermesCLI
 
 
@@ -104,91 +105,24 @@ class TestCLIStatusBar:
         assert "-1" not in text
         assert "0/200K" in text
 
+    def test_input_height_counts_prompt_only_on_first_wrapped_row(self):
+        # Regression for prompt_toolkit classic CLI resize glitches: the prompt
+        # is inserted by BeforeInput only on logical line 0. At three terminal
+        # cells, "⚔ " leaves one cell for the first input character, but
+        # wrapped continuation rows use the full three cells. Estimating every
+        # wrapped row as one-cell wide over-allocates the TextArea and can leave
+        # stale prompt/input cells visible after resize.
+        assert cli_mod._estimate_tui_input_height(["abcdef"], "⚔ ", 3) == 3
+
     def test_input_height_counts_wide_characters_using_cell_width(self):
-        cli_obj = _make_cli()
+        # Prompt width (2 cells) + ten CJK chars (20 cells) = 22 display cells,
+        # which wraps to two rows at 14 terminal columns.
+        assert cli_mod._estimate_tui_input_height(["你" * 10], "❯ ", 14) == 2
 
-        class _Doc:
-            lines = ["你" * 10]
-
-        class _Buffer:
-            document = _Doc()
-
-        input_area = SimpleNamespace(buffer=_Buffer())
-
-        def _input_height():
-            try:
-                from prompt_toolkit.application import get_app
-                from prompt_toolkit.utils import get_cwidth
-
-                doc = input_area.buffer.document
-                prompt_width = max(2, get_cwidth(cli_obj._get_tui_prompt_text()))
-                try:
-                    available_width = get_app().output.get_size().columns - prompt_width
-                except Exception:
-                    import shutil
-                    available_width = shutil.get_terminal_size((80, 24)).columns - prompt_width
-                if available_width < 10:
-                    available_width = 40
-                visual_lines = 0
-                for line in doc.lines:
-                    line_width = get_cwidth(line)
-                    if line_width <= 0:
-                        visual_lines += 1
-                    else:
-                        visual_lines += max(1, -(-line_width // available_width))
-                return min(max(visual_lines, 1), 8)
-            except Exception:
-                return 1
-
-        mock_app = MagicMock()
-        mock_app.output.get_size.return_value = MagicMock(columns=14)
-        with patch.object(HermesCLI, "_get_tui_prompt_text", return_value="❯ "), \
-             patch("prompt_toolkit.application.get_app", return_value=mock_app):
-            assert _input_height() == 2
-
-    def test_input_height_uses_prompt_toolkit_width_over_shutil(self):
-        cli_obj = _make_cli()
-
-        class _Doc:
-            lines = ["你" * 10]
-
-        class _Buffer:
-            document = _Doc()
-
-        input_area = SimpleNamespace(buffer=_Buffer())
-
-        def _input_height():
-            try:
-                from prompt_toolkit.application import get_app
-                from prompt_toolkit.utils import get_cwidth
-
-                doc = input_area.buffer.document
-                prompt_width = max(2, get_cwidth(cli_obj._get_tui_prompt_text()))
-                try:
-                    available_width = get_app().output.get_size().columns - prompt_width
-                except Exception:
-                    import shutil
-                    available_width = shutil.get_terminal_size((80, 24)).columns - prompt_width
-                if available_width < 10:
-                    available_width = 40
-                visual_lines = 0
-                for line in doc.lines:
-                    line_width = get_cwidth(line)
-                    if line_width <= 0:
-                        visual_lines += 1
-                    else:
-                        visual_lines += max(1, -(-line_width // available_width))
-                return min(max(visual_lines, 1), 8)
-            except Exception:
-                return 1
-
-        mock_app = MagicMock()
-        mock_app.output.get_size.return_value = MagicMock(columns=14)
-        with patch.object(HermesCLI, "_get_tui_prompt_text", return_value="❯ "), \
-             patch("prompt_toolkit.application.get_app", return_value=mock_app), \
-             patch("shutil.get_terminal_size") as mock_shutil:
-            assert _input_height() == 2
-        mock_shutil.assert_not_called()
+    def test_input_height_clamps_zero_width_to_one_cell(self):
+        # Some terminals briefly report zero columns during resize. Treat that
+        # as a one-cell terminal rather than falling back to a fake wide width.
+        assert cli_mod._estimate_tui_input_height(["abcd"], "", 0) == 4
 
     def test_build_status_bar_text_no_cost_in_status_bar(self):
         cli_obj = _attach_agent(