fix(ifcdiff): check attributes by default so PredefinedType changes are caught (#8214)

IfcDiff defaulted to relationships=["geometry"], so a plain diff only ever
compared geometry. Attribute-only edits on an element that kept its GlobalId
(a modified or removed PredefinedType, a renamed element, etc.) were silently
missed. The CLI made this worse: --relationships did not list "attributes" or
"geometry" as valid values, so there was no documented way to enable it.

The default is now ["attributes", "geometry"], so a plain `ifcdiff old new`
reports attribute changes alongside geometry changes. The CLI help and the
IfcDiff docstring now document all valid relationship values.

Added a regression test covering a PredefinedType change detected with the
default configuration.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
(cherry picked from commit 0a8ae14789)

src/ifcdiff/ifcdiff.py

@@ -51,8 +51,10 @@ class IfcDiff:
 
     :param old: IFC file object for the old model
     :param new: IFC file object for the new model
-    :param relationships: List of relationships to check. None means that only
-        geometry is compared. See RELATIONSHIP_TYPE for available relationships.
+    :param relationships: List of relationships to check. None means that
+        attributes and geometry are compared, so changes such as a modified or
+        removed PredefinedType are reported. See RELATIONSHIP_TYPE for available
+        relationships.
     :param is_shallow: True if you want only the first difference to be listed.
         False if you want all differences to be checked. Choosing False means
         that comparisons will take longer.
@@ -86,7 +88,7 @@ class IfcDiff:
         self.new = new
         self.change_register = {}
         self.representation_ids = {}
-        self.relationships = relationships or ["geometry"]
+        self.relationships = relationships or ["attributes", "geometry"]
         self.precision = 1e-4
         self.is_shallow = is_shallow
         self.filter_elements = filter_elements
@@ -435,7 +437,11 @@ if __name__ == "__main__":
         "-r",
         "--relationships",
         type=str,
-        help='A list of space-separated relationships, chosen from "type", "property", "container", "aggregate", "classification"',
+        help=(
+            'A list of space-separated relationships, chosen from "attributes", "geometry", '
+            '"type", "property", "container", "aggregate", "classification". '
+            'Defaults to "attributes geometry" when omitted.'
+        ),
         default="",
     )
     args = parser.parse_args()