fix(len): list 特化直接读取 __count__ 字段作为长度

泛型特化方法未生成时，len(list[...]) 按结构体偏移直接读取 __count__，不再误报没有 __len__。

lib/core/Handles/HandlesExprBuiltin.py

@@ -737,6 +737,14 @@ class ExprBuiltinHandle(BaseHandle):
                     result = self.Trans.ExprUtils._try_operator_overLoad(_matched_cn, '__len__', val, Gen)
                     if result is not None:
                         return result
+                    if _matched_cn.startswith('list['):
+                        _count_off: int | None = Gen._get_member_offset('__count__', _matched_cn, pointee)
+                        if _count_off is not None:
+                            _count_ptr = Gen.builder.gep(
+                                val,
+                                [ir.Constant(ir.IntType(32), 0), ir.Constant(ir.IntType(32), _count_off)],
+                                name='list_count_ptr')
+                            return Gen._load(_count_ptr, name='list_count')
                     self._FailFastLenUnsupported(arg_node, Gen, val, f"len() 参数类型 '{_matched_cn}' 没有 __len__ 方法")
                 else:
                     # 未在 Gen.structs 登记的 struct（opaque/匿名）→ fail-fast。

lib/core/Handles/HandlesExprCall.py

@@ -4120,6 +4120,14 @@ class ExprCallHandle(BaseHandle):
                     result = self.Trans.ExprUtils._try_operator_overLoad(_matched_cn, '__len__', val, Gen)
                     if result is not None:
                         return result
+                    if _matched_cn.startswith('list['):
+                        _count_off: int | None = Gen._get_member_offset('__count__', _matched_cn, pointee)
+                        if _count_off is not None:
+                            _count_ptr = Gen.builder.gep(
+                                val,
+                                [ir.Constant(ir.IntType(32), 0), ir.Constant(ir.IntType(32), _count_off)],
+                                name='list_count_ptr')
+                            return Gen._load(_count_ptr, name='list_count')
                     self._FailFastLenUnsupported(arg_node, Gen, val, f"len() 参数类型 '{_matched_cn}' 没有 __len__ 方法")
                 else:
                     # 未在 Gen.structs 登记的 struct（opaque/匿名）→ fail-fast。