Improve tests, downloader, and project config

- Expand blender_downloader with better error handling and platform support
- Add test_main.py for main module tests
- Expand test coverage for introspect and generate_stubs
- Remove reportUnknownMemberType suppression from conformance config
- Exclude conformance/ from ruff linting (docs examples have E402)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_generate_stubs.py

@@ -139,8 +139,7 @@ class TestGenerateFunctionStub(unittest.TestCase):
             "is_classmethod": False,
         }
         result = generate_function_stub(func)
-        self.assertNotIn("*, ", result)
-        self.assertIn("**kwargs", result)
+        self.assertEqual(result, "def foo(x: str, **kwargs: object) -> None: ...\n")
 
     def test_default_before_nondefault_reordered(self) -> None:
         """Non-default params must come before default params."""
@@ -640,6 +639,10 @@ class TestTopologicalSort(unittest.TestCase):
         ]
         result = topological_sort_structs(structs)
         self.assertEqual(len(result), 2)
+        names = [s["name"] for s in result]
+        self.assertEqual(set(names), {"A", "B"})
+        self.assertEqual(names.count("A"), 1)
+        self.assertEqual(names.count("B"), 1)
 
 
 class TestCollectAllMethods(unittest.TestCase):