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>

introspect.py

@@ -959,7 +959,9 @@ def introspect_callable(func: Callable[..., object], name: str) -> FunctionData
     # C functions often use generic names like "object" in __text_signature__
     # while docstrings use descriptive names like "string", "cls", etc.
     doc_param_list = list(param_types.items())
-    sig_param_list = list(sig.parameters.items())
+    sig_param_list = [
+        (n, p) for n, p in sig.parameters.items() if n != "self"
+    ]
 
     params = []
     for i, (pname, param) in enumerate(sig_param_list):
@@ -1223,6 +1225,17 @@ def _fix_dunder_signatures(
                 pass
             continue
 
+        # __iter__: return Iterator[element_type] based on __getitem__
+        if name == "__iter__":
+            try:
+                result = instance[0]
+                etype = _type_name(result)
+                method["return_type"] = f"Iterator[{etype}]"
+                method["params"] = []
+            except Exception:
+                pass
+            continue
+
         # __setitem__: refine value type from __getitem__ return type
         if name == "__setitem__":
             try:
@@ -1381,6 +1394,22 @@ def introspect_class(cls: type[object], module_name: str) -> StructData:
     if dunder_methods:
         _fix_dunder_signatures(cls, dunder_methods)
 
+    # Synthesize __iter__ if the class supports iteration via __getitem__
+    # but doesn't define __iter__ explicitly (old-style C iteration protocol).
+    method_names = {m["name"] for m in methods}
+    if "__getitem__" in method_names and "__iter__" not in method_names:
+        getitem = next(m for m in methods if m["name"] == "__getitem__")
+        elem_type = getitem["return_type"] or "object"
+        methods.append(
+            {
+                "name": "__iter__",
+                "doc": "",
+                "params": [],
+                "return_type": f"Iterator[{elem_type}]",
+                "is_classmethod": False,
+            }
+        )
+
     return {
         "name": cls.__name__,
         "doc": class_doc,