fix(iomodbus): own Export menu via shared engine; fixes dialog teardown crash

2a39bfe folded the xlsx exports into the Catalog menu with hand-rolled handlers
(collect_sheet/collect_all/save_sheets_dialog + bound-method connections),
which broke two things:

1. Teardown crash (tests/iomodbus/test_ui_smoke.py::test_calibration_dialog_
   computes): pytest-qt holds only weakrefs to registered widgets. The shared
   add_export_actions closures (capturing parent) were the only strong,
   C++-anchored reference keeping the MainWindow's Python wrapper alive past
   the test frame; with only weakly-stored bound-method slots left, the window
   wrapper died by refcount at function exit, shiboken deleted the ownerless
   C++ QMainWindow, and the cascade deleted the parented CalibrationDialog's
   C++ object - while the dialog's wrapper survived in qframelesswindow's
   windowEffect reference cycle, so qtbot teardown closed a dead C++ object
   (RuntimeError: Internal C++ object already deleted). Verified by weakref/
   shiboken6.isValid experiments with and without a window-anchoring closure.

2. Wrong menu: spreadsheet export of live grid data is not a device-catalog
   (IOModbus.txt) file operation.

Rework per the Instrument spec: data export gets its own "Export" QToolButton
menu between the Refresh/poll group and the Catalog menu (separator-delimited),
built by the shared add_export_menu_actions engine - restoring the empty-export
notice and the window-anchoring closures. The Catalog menu is back to Import
Devices / Export Devices / Supported Devices. Both menus keep tooltips visible.

Toolbar sizeHint: 1190px themed offscreen (1019px untheme) vs 1240px budget.
Tests: tests/iomodbus 145 passed; full suite 1012 passed, zero errors.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

cim_suite/modules/iomodbus/ui/main_window.py

@@ -34,11 +34,7 @@ from PySide6.QtWidgets import (
 
 from cim_suite.core.ui.chrome import ChromeDialog, StatusFooter
 from cim_suite.core.ui.copy_menu import enable_copy_in
-from cim_suite.core.ui.export_action import (
-    collect_all,
-    collect_sheet,
-    save_sheets_dialog,
-)
+from cim_suite.core.ui.export_action import add_export_menu_actions
 from cim_suite.core.ui.kit import ConnectionChip, InstrumentTabWidget
 
 from .. import config
@@ -313,8 +309,28 @@ class MainWindow(QMainWindow):
         tb.addAction(self.act_log)
 
         tb.addSeparator()
-        # The legacy &Catalog menubar folds into the toolbar (§5.2: single row).
-        # Data-export actions also live here (file-level operations; keeps the toolbar narrow).
+        # Data export (.xlsx) — the shared engine pair, behind an "Export ▾" menu
+        # button instead of two plain toolbar buttons (BL-DS5: with IBM Plex loaded
+        # the flat buttons push sizeHint past the 1240px budget).
+        export_btn = QToolButton(tb)
+        export_btn.setText("Export ▾")
+        self.export_menu = QMenu(export_btn)
+        self.export_menu.setToolTipsVisible(True)  # QMenu hides action tooltips by default
+        self.act_export_tab, self.act_export_all = add_export_menu_actions(
+            self.export_menu, self.tabs, self, self._export_metadata,
+            file_prefix="IOModbus",
+            last_dir=config.export_dir,
+            remember_dir=config.set_export_dir,
+        )
+        self.act_export_tab.setToolTip("Export the active data tab to an Excel workbook.")
+        self.act_export_all.setToolTip("Export all data tabs to a single Excel workbook.")
+        export_btn.setMenu(self.export_menu)
+        export_btn.setPopupMode(QToolButton.ToolButtonPopupMode.InstantPopup)
+        tb.addWidget(export_btn)
+
+        tb.addSeparator()
+        # The legacy &Catalog menubar folds into the toolbar (§5.2: single row) —
+        # device-catalog file operations (IOModbus.txt) only.
         menu_btn = QToolButton(tb)
         menu_btn.setText("Catalog ▾")
         self.catalog_menu = QMenu(menu_btn)
@@ -328,14 +344,6 @@ class MainWindow(QMainWindow):
         self.catalog_menu.addSeparator()
         self.act_supported = self.catalog_menu.addAction("Supported Devices…")
         self.act_supported.triggered.connect(self._show_supported_devices)
-        self.catalog_menu.addSeparator()
-        # Export data — placed here rather than as separate toolbar buttons (BL-DS5: toolbar fit).
-        self.act_export_tab = self.catalog_menu.addAction("Export This Tab…")
-        self.act_export_tab.setToolTip("Export the active data tab to an Excel workbook.")
-        self.act_export_tab.triggered.connect(self._export_this_tab)
-        self.act_export_all = self.catalog_menu.addAction("Export All Tabs…")
-        self.act_export_all.setToolTip("Export all data tabs to a single Excel workbook.")
-        self.act_export_all.triggered.connect(self._export_all_tabs)
         menu_btn.setMenu(self.catalog_menu)
         menu_btn.setPopupMode(QToolButton.ToolButtonPopupMode.InstantPopup)
         tb.addWidget(menu_btn)
@@ -379,24 +387,6 @@ class MainWindow(QMainWindow):
             if self._connector is not None:
                 self._connector(dlg.selected_port(), dlg.selected_baud())
 
-    def _export_this_tab(self) -> None:
-        meta = self._export_metadata()
-        idx = self.tabs.currentIndex()
-        sheet = collect_sheet(self.tabs, idx, meta)
-        label = self.tabs.tabText(idx)
-        if sheet:
-            save_sheets_dialog(
-                self, f"IOModbus_{label}.xlsx", [sheet],
-                last_dir=config.export_dir, remember_dir=config.set_export_dir,
-            )
-
-    def _export_all_tabs(self) -> None:
-        sheets = collect_all(self.tabs, self._export_metadata())
-        save_sheets_dialog(
-            self, "IOModbus_AllTabs.xlsx", sheets,
-            last_dir=config.export_dir, remember_dir=config.set_export_dir,
-        )
-
     def _scan(self) -> None:
         start, end = parse_address_range(self.addr_edit.text())
         self._ctrl.scan(start, end)

tests/iomodbus/test_main_window_toolbar.py

@@ -30,13 +30,20 @@ def test_chip_tracks_connection(window):
 
 
 def test_catalog_menu_replaces_the_menubar(window):
+    # Catalog ▾ is device-catalog file operations (IOModbus.txt) only.
     labels = [a.text() for a in window.catalog_menu.actions() if a.text()]
-    assert any("Import Devices" in t for t in labels)
-    assert any("Export Devices" in t for t in labels)
-    assert any("Supported Devices" in t for t in labels)
+    assert labels == ["Import Devices…", "Export Devices…", "Supported Devices…"]
     assert window.menuBar().actions() == []  # the old menubar is gone
 
 
+def test_export_menu_holds_the_data_exports(window):
+    # Spreadsheet export lives in its own Export ▾ menu, via the shared core engine.
+    labels = [a.text() for a in window.export_menu.actions() if a.text()]
+    assert labels == ["Export This Tab…", "Export All Tabs…"]
+    assert window.act_export_tab.text() == "Export This Tab…"
+    assert window.act_export_all.text() == "Export All Tabs…"
+
+
 def test_disconnect_stops_controller(window, monkeypatch):
     stopped = []
     monkeypatch.setattr(window._ctrl, "stop", lambda: stopped.append(True))