fix: use append instead of fragile insert chain in PartDesign menu (#57)

Replace the chained insert operations in modifyMenuBar() with independent
append operations. The old approach anchored on PartDesign_Boolean and
chained each subsequent command off the previous insertion — a single
missing anchor caused a cascade failure.

The new approach uses append with PartDesign_Body as the parent locator.
Each operation is independent, so a failure in one does not affect the
others.

ztools/InitGui.py

@@ -66,13 +66,8 @@ class ZToolsWorkbench(Gui.Workbench):
         except Exception:
             pass
 
-        from ztools.commands import (
-            assembly_pattern_commands,
-            datum_commands,
-            pattern_commands,
-            pocket_commands,
-            spreadsheet_commands,
-        )
+        # Command imports moved to module scope (after Gui.addWorkbench) so they
+        # are available before Initialize() runs.  See end of file.
 
         # =====================================================================
         # PartDesign Structure Tools
@@ -306,12 +301,6 @@ class ZToolsWorkbench(Gui.Workbench):
             + self.ztools_spreadsheet_tools,
         )
 
-        # Register the PartDesign manipulator now that commands exist.
-        # Guard so it only registers once even if Initialize is called again.
-        if not getattr(ZToolsWorkbench, "_manipulator_installed", False):
-            ZToolsWorkbench._manipulator_installed = True
-            Gui.addWorkbenchManipulator(_ZToolsPartDesignManipulator())
-
         App.Console.PrintMessage("ztools workbench initialized\n")
 
     def Activated(self):
@@ -337,11 +326,24 @@ class ZToolsWorkbench(Gui.Workbench):
 Gui.addWorkbench(ZToolsWorkbench())
 
 
+# ---------------------------------------------------------------------------
+# Eager command registration
+# ---------------------------------------------------------------------------
+# Import command modules at module scope so Gui.addCommand() calls run before
+# any workbench activates.  This ensures the PartDesign manipulator can
+# reference them regardless of workbench activation order (#52).
+
+from ztools.commands import (
+    assembly_pattern_commands,
+    datum_commands,
+    pattern_commands,
+    pocket_commands,
+    spreadsheet_commands,
+)
+
 # ---------------------------------------------------------------------------
 # WorkbenchManipulator: inject ZTools commands into PartDesign workbench
 # ---------------------------------------------------------------------------
-# Registered in ZToolsWorkbench.Initialize() after commands are imported,
-# so the commands exist before the manipulator references them.
 
 
 class _ZToolsPartDesignManipulator:
@@ -363,24 +365,11 @@ class _ZToolsPartDesignManipulator:
 
     def modifyMenuBar(self):
         return [
-            {
-                "insert": "ZTools_DatumCreator",
-                "menuItem": "PartDesign_Boolean",
-                "after": "",
-            },
-            {
-                "insert": "ZTools_DatumManager",
-                "menuItem": "ZTools_DatumCreator",
-                "after": "",
-            },
-            {
-                "insert": "ZTools_EnhancedPocket",
-                "menuItem": "ZTools_DatumManager",
-                "after": "",
-            },
-            {
-                "insert": "ZTools_RotatedLinearPattern",
-                "menuItem": "ZTools_EnhancedPocket",
-                "after": "",
-            },
+            {"append": "ZTools_DatumCreator", "menuItem": "PartDesign_Body"},
+            {"append": "ZTools_DatumManager", "menuItem": "PartDesign_Body"},
+            {"append": "ZTools_EnhancedPocket", "menuItem": "PartDesign_Body"},
+            {"append": "ZTools_RotatedLinearPattern", "menuItem": "PartDesign_Body"},
         ]
+
+
+Gui.addWorkbenchManipulator(_ZToolsPartDesignManipulator())