fix(tui): status bar duplicates and degrades during long sessions (#3291)

shutil.get_terminal_size() can return stale/fallback values on SSH that
differ from prompt_toolkit's actual terminal width. Fragments built for
the wrong width overflow and wrap onto a second line (wrap_lines=True
default), appearing as progressively degrading duplicates.

- Read width from get_app().output.get_size().columns when inside a
  prompt_toolkit TUI, falling back to shutil outside TUI context
- Add wrap_lines=False on the status bar Window as belt-and-suspenders
  guard against any future width mismatch

Closes #3130

Co-authored-by: Mibayy <Mibayy@users.noreply.github.com>

tests/test_cli_status_bar.py

@@ -182,3 +182,94 @@ class TestCLIUsageReport:
         assert "Total cost:" in output
         assert "n/a" in output
         assert "Pricing unknown for glm-5" in output
+
+
+class TestStatusBarWidthSource:
+    """Ensure status bar fragments don't overflow the terminal width."""
+
+    def _make_wide_cli(self):
+        from datetime import datetime, timedelta
+        cli_obj = _attach_agent(
+            _make_cli(),
+            prompt_tokens=100_000,
+            completion_tokens=5_000,
+            total_tokens=105_000,
+            api_calls=20,
+            context_tokens=100_000,
+            context_length=200_000,
+        )
+        cli_obj._status_bar_visible = True
+        return cli_obj
+
+    def test_fragments_fit_within_announced_width(self):
+        """Total fragment text length must not exceed the width used to build them."""
+        from unittest.mock import MagicMock, patch
+        cli_obj = self._make_wide_cli()
+
+        for width in (40, 52, 76, 80, 120, 200):
+            mock_app = MagicMock()
+            mock_app.output.get_size.return_value = MagicMock(columns=width)
+
+            with patch("prompt_toolkit.application.get_app", return_value=mock_app):
+                frags = cli_obj._get_status_bar_fragments()
+
+            total_text = "".join(text for _, text in frags)
+            assert len(total_text) <= width + 4, (  # +4 for minor padding chars
+                f"At width={width}, fragment total {len(total_text)} chars overflows "
+                f"({total_text!r})"
+            )
+
+    def test_fragments_use_pt_width_over_shutil(self):
+        """When prompt_toolkit reports a width, shutil.get_terminal_size must not be used."""
+        from unittest.mock import MagicMock, patch
+        cli_obj = self._make_wide_cli()
+
+        mock_app = MagicMock()
+        mock_app.output.get_size.return_value = MagicMock(columns=120)
+
+        with patch("prompt_toolkit.application.get_app", return_value=mock_app) as mock_get_app, \
+             patch("shutil.get_terminal_size") as mock_shutil:
+            cli_obj._get_status_bar_fragments()
+
+        mock_shutil.assert_not_called()
+
+    def test_fragments_fall_back_to_shutil_when_no_app(self):
+        """Outside a TUI context (no running app), shutil must be used as fallback."""
+        from unittest.mock import MagicMock, patch
+        cli_obj = self._make_wide_cli()
+
+        with patch("prompt_toolkit.application.get_app", side_effect=Exception("no app")), \
+             patch("shutil.get_terminal_size", return_value=MagicMock(columns=100)) as mock_shutil:
+            frags = cli_obj._get_status_bar_fragments()
+
+        mock_shutil.assert_called()
+        assert len(frags) > 0
+
+    def test_build_status_bar_text_uses_pt_width(self):
+        """_build_status_bar_text() must also prefer prompt_toolkit width."""
+        from unittest.mock import MagicMock, patch
+        cli_obj = self._make_wide_cli()
+
+        mock_app = MagicMock()
+        mock_app.output.get_size.return_value = MagicMock(columns=80)
+
+        with patch("prompt_toolkit.application.get_app", return_value=mock_app), \
+             patch("shutil.get_terminal_size") as mock_shutil:
+            text = cli_obj._build_status_bar_text()  # no explicit width
+
+        mock_shutil.assert_not_called()
+        assert isinstance(text, str)
+        assert len(text) > 0
+
+    def test_explicit_width_skips_pt_lookup(self):
+        """An explicit width= argument must bypass both PT and shutil lookups."""
+        from unittest.mock import patch
+        cli_obj = self._make_wide_cli()
+
+        with patch("prompt_toolkit.application.get_app") as mock_get_app, \
+             patch("shutil.get_terminal_size") as mock_shutil:
+            text = cli_obj._build_status_bar_text(width=100)
+
+        mock_get_app.assert_not_called()
+        mock_shutil.assert_not_called()
+        assert len(text) > 0