refactor(auth): Disable Nous legacy session key fallback

hermes_cli/proxy/adapters/base.py

@@ -69,11 +69,11 @@ class UpstreamAdapter(ABC):
 
     @abstractmethod
     def get_credential(self) -> UpstreamCredential:
-        """Return a fresh credential, refreshing/minting if necessary.
+        """Return a fresh credential, refreshing or rotating if necessary.
 
         Implementations should:
           - refresh the access token if it's near expiry
-          - mint/rotate the upstream bearer key if it's near expiry
+          - rotate the upstream bearer key if it's near expiry
           - persist any refreshed state back to disk
 
         Raises:
@@ -90,8 +90,7 @@ class UpstreamAdapter(ABC):
         """Return an alternate credential after an upstream auth failure.
 
         The default is no retry. Providers can override this for one-shot
-        fallback paths, such as switching from a preferred token type to a
-        legacy bearer after the upstream rejects the first request.
+        fallback paths after the upstream rejects the first request.
         """
         _ = failed_credential, status_code
         return None