Implement batched Firebase writes

add disconnect button and solve live frame glitching issue

implemented Live Cam feature

enhanced code clarity, consistency, maintainability

solved the frame glitch bug, enable user to continue session and top up kpi total

fixed counts overwritten to 0 bug

aggregate entry and exit data to kpi card and bar chart

can configure for both cam but can't run inference at the same time

create utility file to store reused math logic, add modal path to config file

fix direction issue, remove redundant button, enable model to run on cuda (faster)

complete phase 1