fix: improve bpm reliability

perf: optimize signal processing pipeline and cleanup frontend

chore: setup deployment for Hugging Face with Docker and dynamic URLs

feat: migrate rPPG pipeline to FaceLandmarker and 5-method adaptive extraction

fix: enforce minimum autocorrelation search range of 50 lags regardless of fps

fix: move ROI from buggy forehead to cheeks with correct centering

fix: compute effective FPS from timespan to handle bursty WebSocket delivery

fix: improve BPM accuracy with first-peak autocorrelation and bandpass fix

feat: websocket endpoint, frontend utilities, face detection and pulse hook