[Update] `Plum` playground

[1chooo]

The current codebase of the Plum Playground is still quite messy and needs to be integrated into the Refinaid package. Additionally, each time Plum is launched, there is a delay due to retraining the model. Therefore, it is necessary to implement logic to detect if a model already exists and skip the training process when it does. This will help improve our execution speed.