Refactor model loading and prediction handling

Add files via upload

Delete backend/models/best_xgboost.pkl

Update requirements.txt

Update app.py

Update requirements.txt

Implement model extraction from zip files

Rename best_cnn (1).keras to best_cnn.keras

Add files via upload

Delete backend/models/best_transformer.keras.zip

Delete backend/models/best_lstm.keras.zip

Delete backend/models/best_cnn.keras.zip

Refactor model loading and add debug info

Add files via upload

Delete backend/models/best_lstm.keras