ifcwrap: rename geometry backref helper to fix stub validation crash

The #1124 fix (824c1fc280) named its pythoncode backref helper
`_geometry_with_backref` with a leading underscore. validate_stub.py's
get_function_node_name() skips any leading-underscore name (its only
exception is `_is`), so the helper never gets added to the parsed
`subnames` set. When get_names_tree_lines() later processes
`geometry = property(_geometry_with_backref)`, find_method_by_name()
can't find the backing function and the `assert (wrapped_function :=
find_method_by_name(arg))` at validate_stub.py:154 raises AssertionError
instead of the expected clean stub/wrapper diff, crashing the CI
`ci.yml` -> compile-and-test -> "Test ifcopenshell-python" step
(`make test-parallel`) on every push since 824c1fc280.

Renaming to `geometry_with_backref_` (trailing underscore) matches the
existing local convention in the same class bodies for backing-
implementation helpers (calc_volume_, calc_surface_area_), which
validate_stub.py's heuristic already handles correctly.

Also add the six new SVG edge-classification settings-flag classes
(SvgEmitFlushEdges, SvgRenderCreaseEdges, SvgRenderSharpEdges,
SvgRidgeAngleMinDegrees, SvgUseEdgeClassification,
SvgValleyAngleMinDegrees) to ifcopenshell_wrapper.pyi. These were added
to the C++/SWIG side by the SVG edge classification commits but never
synced to the stub, and validate_stub would report them as a
stub/wrapper discrepancy once the crash above is fixed.

Reproduced by building ifcopenshell against the exact CI-tested commit
(c68e4a0eee) with SWIG 4.1.0 (matching ci.yml's pinned build-from-source
version) and running validate_stub.py's actual logic against the
generated ifcopenshell_wrapper.py: crashed identically to the CI log
before this change, passed cleanly after. test/util/scripts/test_validate_stub.py::TestValidateStub::test_run
passes against the rebuilt wrapper.

Generated with the assistance of an AI coding tool.

src/ifcopenshell-python/ifcopenshell/ifcopenshell_wrapper.pyi

@@ -484,6 +484,26 @@ class Settings:
     def set_(self, *args): ...
     def setting_names(self): ...
 
+class SvgEmitFlushEdges:
+    defaultvalue: Any
+    description: Any
+    name: Any
+
+class SvgRenderCreaseEdges:
+    defaultvalue: Any
+    description: Any
+    name: Any
+
+class SvgRenderSharpEdges:
+    defaultvalue: Any
+    description: Any
+    name: Any
+
+class SvgRidgeAngleMinDegrees:
+    defaultvalue: Any
+    description: Any
+    name: Any
+
 class SvgSerializer(WriteOnlyGeometrySerializer):
     def __init__(self, out_filename, geometry_settings, settings, logger=None): ...
     SH_NONE: Any
@@ -548,6 +568,16 @@ class SvgSerializer(WriteOnlyGeometrySerializer):
     def write(self, *args): ...
     def writeHeader(self): ...
 
+class SvgUseEdgeClassification:
+    defaultvalue: Any
+    description: Any
+    name: Any
+
+class SvgValleyAngleMinDegrees:
+    defaultvalue: Any
+    description: Any
+    name: Any
+
 class SwigPyIterator:
     def __init__(self, *args, **kwargs): ...
     def advance(self, n): ...

src/ifcwrap/IfcGeomWrapper.i

@@ -794,11 +794,11 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
 	%pythoncode %{
         # Hide the getters with read-only property implementations
         # Keep the owning element alive while its geometry is referenced (#1124).
-        def _geometry_with_backref(self, _f=geometry):
+        def geometry_with_backref_(self, _f=geometry):
             result = _f(self)
             result._parent = self
             return result
-        geometry = property(_geometry_with_backref)
+        geometry = property(geometry_with_backref_)
 	%}
 };
 
@@ -806,11 +806,11 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
 	%pythoncode %{
         # Hide the getters with read-only property implementations
         # Keep the owning element alive while its geometry is referenced (#1124).
-        def _geometry_with_backref(self, _f=geometry):
+        def geometry_with_backref_(self, _f=geometry):
             result = _f(self)
             result._parent = self
             return result
-        geometry = property(_geometry_with_backref)
+        geometry = property(geometry_with_backref_)
 	%}
 };
 
@@ -836,11 +836,11 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
     %pythoncode %{
         # Hide the getters with read-only property implementations
         # Keep the owning element alive while its geometry is referenced (#1124).
-        def _geometry_with_backref(self, _f=geometry):
+        def geometry_with_backref_(self, _f=geometry):
             result = _f(self)
             result._parent = self
             return result
-        geometry = property(_geometry_with_backref)
+        geometry = property(geometry_with_backref_)
         volume = property(calc_volume_)
         surface_area = property(calc_surface_area_)
     %}