Use Wi-Fi as a motion sensor

Some phones have access to WiFi CSI, which allows **through wall** motion detection on Nexus 5 and Nexus 6p. Check out `nexmon_csi` Github repo.

Could Wi-Fi sensing be added to the list of motion triggers for the project?

The issue names no Haven files, tests, or entry points. Start by locating the existing motion-trigger implementation and reviewing the referenced nexmon_csi repository and supported Nexus devices; done means Wi-Fi sensing is integrated as a motion trigger with its support and behavior documented.

Written by the indexing model from the issue text.