Proper fix for model discovery per provider

providers/base.py

@@ -221,3 +221,27 @@ class ModelProvider(ABC):
     def supports_thinking_mode(self, model_name: str) -> bool:
         """Check if the model supports extended thinking mode."""
         pass
+
+    @abstractmethod
+    def list_models(self, respect_restrictions: bool = True) -> list[str]:
+        """Return a list of model names supported by this provider.
+
+        Args:
+            respect_restrictions: Whether to apply provider-specific restriction logic.
+
+        Returns:
+            List of model names available from this provider
+        """
+        pass
+
+    @abstractmethod
+    def list_all_known_models(self) -> list[str]:
+        """Return all model names known by this provider, including alias targets.
+
+        This is used for validation purposes to ensure restriction policies
+        can validate against both aliases and their target model names.
+
+        Returns:
+            List of all model names and alias targets known by this provider
+        """
+        pass