fix: add logging to debug auth issues

backend/src/app/core/auth.py

@@ -1,3 +1,4 @@
+import logging
 from dataclasses import dataclass
 from uuid import UUID
 
@@ -12,6 +13,7 @@ from app.core.database import get_session
 from app.models.nuzlocke_run import NuzlockeRun
 from app.models.user import User
 
+logger = logging.getLogger(__name__)
 _jwks_client: PyJWKClient | None = None
 
 
@@ -71,12 +73,14 @@ def _verify_jwt(token: str) -> dict | None:
                 algorithms=["RS256", "ES256"],
                 audience="authenticated",
             )
-        except jwt.InvalidTokenError:
-            pass
-        except PyJWKClientError:
-            pass
-        except PyJWKSetError:
-            pass
+        except jwt.InvalidTokenError as e:
+            logger.warning("JWKS JWT validation failed: %s", e)
+        except PyJWKClientError as e:
+            logger.warning("JWKS client error: %s", e)
+        except PyJWKSetError as e:
+            logger.warning("JWKS set error: %s", e)
+    else:
+        logger.debug("No JWKS client available (SUPABASE_URL not set?)")
     return _verify_jwt_hs256(token)