refactor: remove unused import from app_mcp.py

- Removed the unused `pywt` import to clean up the code and improve readability.

app_mcp.py

@@ -17,7 +17,6 @@ from utils.gradient import gradient_processing
 from utils.minmax import preprocess as minmax_preprocess
 from utils.ela import genELA as ELA
 from forensics.registry import register_model, MODEL_REGISTRY, ModelEntry
-import pywt
 import cv2
 import tempfile
 import exiftool