Stores one row per finished session of the host in the custom table host_session (schema 0.0.1): start and end time, duration, mean and max of CPU, RAM and disk percentage, and coverage (share of the session's minutes with a CPU sample). The hub adds the gateway as spoke_id.

Runs every minute. The current boot comes from /proc/uptime. The previous session is found in the history of the uptime signal (63) before that boot: its last sample is the end, end minus that sample's uptime is the start. A session already stored (start within two minutes) is skipped, so repeated runs write nothing twice. The first row appears after the first reboot that follows the uptime signal's creation (2026-11-06 18:38).

Signal ids are deb13-kde's in the home core. Needs only requests in the image.