Bonsai: fix Apply Opening crash on non-fillings

The + gizmo previously appeared whenever a fillable host and any
non-host object were selected, so clicking it against an IfcCovering
crashed the geometry kernel when the opening generator tried to derive
a shape it couldn't build (AttributeError on 'NoneType.wrapped_data').

Tighten the gizmo poll to require the secondary selection to be a
class the operator can dispatch on: IfcDoor, IfcWindow,
IfcOpeningElement, or a non-IFC mesh. Make the poll selection-order-
independent so either click order activates it. Validate the same
class set at the operator boundary so keymap or scripted invocations
report a clear warning instead of crashing.

The narrower Door/Window support in the opening generator is a Bonsai
implementation limit, not an IFC schema restriction —
IfcRelFillsElement.RelatedBuildingElement is typed as IfcElement and
the schema permits any subtype. The tooltip and inline comment on the
validation branch note this so a future reader knows the gate is
future-work, not schema-mandated.

Rewrite the operator's bl_description to end-user-friendly wording that
drops the internal terms matrix_world and rl1/rl2.

Fixes #8215.

Generated with the assistance of an AI coding tool.

src/bonsai/test/bim/module/model/test_host_add_opening_gizmo.py

@@ -51,6 +51,10 @@ _IFC_CLASS_BY_KIND = {
     "slab": "IfcSlab",
     "roof": "IfcRoof",
     "plain": "IfcDiscreteAccessory",
+    "door": "IfcDoor",
+    "window": "IfcWindow",
+    "opening": "IfcOpeningElement",
+    "covering": "IfcCovering",
 }
 
 
@@ -168,6 +172,40 @@ def test_poll_rejects_host_host_pairs(active_kind, other_kind, patched_tool):
     assert _run_poll(patched_tool, active_kind=active_kind, other_kind=other_kind) is False
 
 
+@pytest.mark.parametrize("filling_kind", ["door", "window", "opening", "mesh"])
+def test_poll_accepts_host_with_supported_filling(filling_kind, patched_tool):
+    """The apply-opening gizmo must activate when the secondary selection
+    is a class the operator can dispatch on: ``IfcDoor`` / ``IfcWindow``
+    (filled openings), ``IfcOpeningElement`` (existing opening reassigned
+    to a new host), or a raw Blender mesh (converted to an opening)."""
+    assert _run_poll(patched_tool, active_kind="wall", other_kind=filling_kind) is True
+
+
+@pytest.mark.parametrize("non_filling_kind", ["covering", "plain"])
+def test_poll_rejects_host_with_non_filling(non_filling_kind, patched_tool):
+    """An IFC entity whose class the apply-opening operator can't dispatch
+    on must keep the gizmo hidden — clicking it would otherwise dispatch
+    the operator on a class whose geometry the opening generator can't
+    derive, causing a deep traceback in the geometry kernel."""
+    assert _run_poll(patched_tool, active_kind="wall", other_kind=non_filling_kind) is False
+
+
+@pytest.mark.parametrize("filling_kind", ["door", "window", "opening", "mesh"])
+def test_poll_accepts_filling_active_with_host_other(filling_kind, patched_tool):
+    """The poll must be selection-order independent: the icon should appear
+    whether the user clicked the host first or the filling first. The
+    operator handles either order, so the gizmo should match."""
+    assert _run_poll(patched_tool, active_kind=filling_kind, other_kind="wall") is True
+
+
+@pytest.mark.parametrize("non_filling_kind", ["covering", "plain"])
+def test_poll_rejects_non_filling_active_with_host_other(non_filling_kind, patched_tool):
+    """The selection-order independence must not loosen the filling
+    predicate — covering + wall stays rejected regardless of which is
+    active."""
+    assert _run_poll(patched_tool, active_kind=non_filling_kind, other_kind="wall") is False
+
+
 def test_poll_rejects_active_host_without_has_openings(patched_tool):
     # Real-world equivalent: an IFC class that the active schema strips
     # ``HasOpenings`` from (e.g., a non-element subtype). The active sentinel
@@ -265,12 +303,16 @@ def _run_position_layer3_branch(
     icon = SimpleNamespace(matrix_basis=None, hide=True)
     self_stub = SimpleNamespace(add_opening_icon=icon)
 
-    host_element = object()
+    # Host identification in the gizmo branches on the entity's class, so
+    # the sentinel must respond to ``is_a``. The non-host selection has no
+    # IFC entity (mesh-like) and is accepted as a filling.
+    host_element = _FakeIfcEntity("IfcSlab")
+    entity_map = {id(host_obj): host_element, id(other): None}
     with contextlib.ExitStack() as stack:
         stack.enter_context(
             patched_tool(
                 selected_list=selected,
-                entity=host_element,
+                entity=lambda o: entity_map.get(id(o)),
                 modifier_predicates={"is_path_connectable_wall": is_path_connectable_wall},
             )
         )