Fix handler registration order in Scene (#1642)

* Fix handler registration order in `Scene`

Previously, `Scene` handlers were registered based on the sorted output of `inspect.getmembers`, causing incorrect execution order. Now, handlers are registered in the order they are defined in the class, ensuring reliable behavior and proper sequence when handling filters with varying specificity. Added test cases to validate the correct handler ordering.

* Add dynamic dataclass and class attribute resolvers

Introduced `dataclass_kwargs` to ensure compatibility with different Python versions and modular attribute handling. Added utilities for resolving class attributes dynamically, enhancing flexibility with MRO-based resolvers. Updated tests to verify new features and ensure proper functionality across various scenarios.

* Update changelog

tests/test_fsm/test_scene.py

@@ -1680,3 +1680,73 @@ class TestSceneInheritance:
         assert child_2_handler.handler is _empty_handler
 
         assert child_3_handler.handler is not _empty_handler
+
+
+def collect_handler_names(scene):
+    return [handler.handler.__name__ for handler in scene.__scene_config__.handlers]
+
+
+class TestSceneHandlersOrdering:
+    def test_correct_ordering(self):
+        class Scene1(Scene):
+            @on.message()
+            async def handler1(self, message: Message) -> None:
+                pass
+
+            @on.message()
+            async def handler2(self, message: Message) -> None:
+                pass
+
+        class Scene2(Scene):
+            @on.message()
+            async def handler2(self, message: Message) -> None:
+                pass
+
+            @on.message()
+            async def handler1(self, message: Message) -> None:
+                pass
+
+        assert collect_handler_names(Scene1) == ["handler1", "handler2"]
+        assert collect_handler_names(Scene2) == ["handler2", "handler1"]
+
+    def test_inherited_handlers_follow_mro_order(self):
+        class Scene1(Scene):
+            @on.message()
+            async def handler1(self, message: Message) -> None:
+                pass
+
+            @on.message()
+            async def handler2(self, message: Message) -> None:
+                pass
+
+        class Scene2(Scene1):
+            @on.message()
+            async def handler3(self, message: Message) -> None:
+                pass
+
+            @on.message()
+            async def handler4(self, message: Message) -> None:
+                pass
+
+        assert collect_handler_names(Scene2) == ["handler3", "handler4", "handler1", "handler2"]
+
+    def test_inherited_overwrite_follow_mro_order(self):
+        class Scene1(Scene):
+            @on.message()
+            async def handler1(self, message: Message) -> None:
+                pass
+
+            @on.message()
+            async def handler2(self, message: Message) -> None:
+                pass
+
+        class Scene2(Scene1):
+            @on.message()
+            async def handler2(self, message: Message) -> None:
+                pass
+
+            @on.message()
+            async def handler3(self, message: Message) -> None:
+                pass
+
+        assert collect_handler_names(Scene2) == ["handler3", "handler1", "handler2"]