Remove Wan2 model files, including configuration, attention mechanisms, and utility functions, to streamline the codebase and eliminate unused components. This cleanup enhances maintainability and focuses on the core functionality of the Wan2 module.

tests/wan_test_helpers.py

@@ -3,7 +3,7 @@
 
 def _make_tiny_config():
     """Create a tiny WanModelConfig for testing."""
-    from mlx_video.models.wan2.config import WanModelConfig
+    from mlx_video.models.wan_2.config import WanModelConfig
 
     config = WanModelConfig()
     # Override to tiny values