Implementing ZADD If Key Exists

I recently had to make some performance optimizations. These are my favorite kind of coding task as they usually require some sort of creativity and tradeoff. This time around I also learned more about Redis and practiced using AI to generate code. During my refactor, I came across a need to upsert a `(member, score)` into a Redis sorted set only if the Redis sorted set exists. This upsert would…