* db: add back last_seen to the database Fixes #2574 Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com> * integration: ensure last_seen is set Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com> --------- Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>