fix: CPU-safe inference for HF free tier

Update: model.py and app.py to remove multiple instances of same methods and add quantization (f16) to reduce inference time

fix: remove duplicate CORS middleware configuration

feat: add /predict_frames endpoint and frame-based preprocessing to FastAPI service

feat: add /predict_frames endpoint and frame-based preprocessing to FastAPI service

update: api calls and data preprocessing

add: app.py API calls