feat: A toggles the sessions column between active and archived

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_tui.py

@@ -310,7 +310,7 @@ async def test_new_session_on_dismiss_sequential_create_then_refresh():
                 session=MagicMock(), spawn_ok=True, spawn_error=""
             )
 
-        async def fake_list(project_id):
+        async def fake_list(project_id, archived=False):
             call_order.append("list")
             return []
 
@@ -2088,3 +2088,42 @@ async def test_archive_session_action_calls_service_and_refreshes():
 
         mock_service.archive_session.assert_awaited_once_with(sess_id)
         mock_service.list_sessions.assert_awaited()
+
+
+@pytest.mark.asyncio
+async def test_toggle_archived_binding_exists():
+    bindings = {b.key: b for b in HqtApp.BINDINGS}
+    assert bindings["A"].action == "toggle_archived"
+
+
+@pytest.mark.asyncio
+async def test_toggle_archived_switches_list_and_header():
+    app = HqtApp()
+    async with app.run_test(size=(120, 40)) as pilot:
+        from hqt.tui.widgets.session_list import SessionList
+        from textual.widgets import Label
+
+        proj_id = 42
+        app._selected_project_id = proj_id
+
+        mock_service = MagicMock()
+        mock_service.list_sessions = AsyncMock(return_value=[])
+        mock_service.sync_window_labels = AsyncMock(return_value=[])
+        app._session_service = mock_service
+
+        assert app._show_archived is False
+
+        await app.run_action("toggle_archived")
+        await pilot.pause()
+
+        assert app._show_archived is True
+        mock_service.list_sessions.assert_awaited_with(proj_id, archived=True)
+        header = app.query_one(SessionList).query_one("#session-header", Label)
+        assert "archived" in str(header.render()).lower()
+
+        await app.run_action("toggle_archived")
+        await pilot.pause()
+
+        assert app._show_archived is False
+        mock_service.list_sessions.assert_awaited_with(proj_id, archived=False)
+        assert str(header.render()) == "Sessions"