fix(session): enable JSON serialization for Valkey sessions

- Set SESSION_REDIS_JSON for the Redis-backed session configuration.
- Match session serialization to the client's decoded string responses.
- Leave the fallback session backend unchanged.

my_modules/app/setup.py

@@ -61,6 +61,7 @@ if os.getenv("VALKEY_HOST", None) is not None:
       db=os.getenv('VALKEY_DB', 0),
       decode_responses=True,
     ),
+    SESSION_REDIS_JSON=True,
   )
 else:
   app.config.from_mapping(