packaging: Fix base model_post_init to not wipe self._ordered_pins ...

Author: robtaylor

chipflow_lib/packaging/base.py

@@ -48,7 +48,7 @@ def model_post_init(self, __context):
         """Initialize internal tracking structures"""
         self._interfaces: Dict[str, dict] = {}
         self._components: Dict[str, wiring.Component] = {}
-        self._ordered_pins = None  # Subclasses should set this
+        assert self._ordered_pins is not None, "Subclass must set self._ordered_pins in model_post_init"
         return super().model_post_init(__context)
 
     def register_component(self, name: str, component: wiring.Component) -> None: