report stable ID failure

src/submission/submit.py

@@ -132,7 +132,8 @@ def fetch_sub_claim(oauth_token: gr.OAuthToken | None) -> dict | None:
             "preferred_username": claims.get("preferred_username"),
             "name": claims.get("name"),
         }
-    except Exception:
+    except Exception as e:
+        logger.warning(f"Failed to fetch user claims: {e}")
         return None