ifcpatch: use stdlib graphlib for Optimise topological sort (#4399)

The Optimise recipe imported `toposort`, a third-party PyPI package that
is not bundled with Bonsai, so running the recipe there raised
`ModuleNotFoundError: No module named 'toposort'`.

Replace it with the standard library `graphlib.TopologicalSorter`
(available since Python 3.9), which provides the same dependencies-first
ordering guarantee the recipe relies on: forward-referenced instances are
mapped before the instances that reference them. The dependency-graph
dict format ({node: {predecessors}}) is identical between the two, so the
graph construction is unchanged. Drop `toposort` from ifcpatch's
dependencies since it is no longer used.

Verified with toposort NOT installed: the Optimise recipe now runs and
deduplicates correctly (IfcParseExamples_test.ifc 88 -> 63 instances, all
6 products preserved, output reopens cleanly).

Generated with the assistance of an AI coding tool.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
(cherry picked from commit 382f5e0c21)

src/ifcpatch/pyproject.toml

@@ -15,7 +15,7 @@ classifiers = [
     "Programming Language :: Python :: 3",
     "License :: OSI Approved :: GNU Lesser General Public License v3 or later (LGPLv3+)",
 ]
-dependencies = ["ifcopenshell", "toposort", "numpy"]
+dependencies = ["ifcopenshell", "numpy"]
 
 [project.optional-dependencies]
 advanced = [