Generalize the single config.system bbox into a named config.monitoring_areas list with set-union semantics (kept if geometry intersects ANY area; no-geom always kept; empty list keeps everything). Migration 042 seeds 'default' from the existing bounds (49.0/41.8/-111/-117.5); old monitor_* columns preserved for v0.14.1. Archive + supervisor both apply the list. GUI /monitoring-area gains list/create/update/delete + multi-rectangle map.
