Add conformance tests and fix introspection issues

- Add conformance test framework with poe conformance task
- Add test files for mathutils, bpy, and gpu API patterns
- Fix self param leaking into signatures from C method_descriptors
- Synthesize __iter__ for classes with __getitem__ but no explicit __iter__
- Add __iter__ runtime probing to discover Iterator[element_type]
- Add :raises to directive lookahead to fix rtype parsing
- Add 5.1 override for Matrix.Translation to accept Vector

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

conformance/test_mathutils.py

@@ -0,0 +1,18 @@
+import mathutils
+from math import radians
+
+vec = mathutils.Vector((1.0, 2.0, 3.0))
+
+mat_rot = mathutils.Matrix.Rotation(radians(90.0), 4, "X")
+mat_trans = mathutils.Matrix.Translation(vec)
+
+mat = mat_trans @ mat_rot
+mat.invert()
+
+mat3 = mat.to_3x3()
+quat1 = mat.to_quaternion()
+quat2 = mat3.to_quaternion()
+
+quat_diff = quat1.rotation_difference(quat2)
+
+print(quat_diff.angle)