Backfill 71 missing SERVICE_TERRITORY geometries (incl. VEC)

71 regions of type SERVICE_TERRITORY have metadata but no territories row (no geometry). VEC (eia_id 19791, region-st-19791) is in this bucket — surfaced by Relay map bug 2026-05-08. Sources to check: HIFLD Electric Retail Service Territories, EIA-861 service territory KML/shapefile exports. Source eia_ids list: SELECT r.eia_id, r.slug FROM regions r LEFT JOIN territories t ON t.region_id = r.id WHERE r.type = SERVICE_TERRITORY AND t.region_id IS NULL ORDER BY r.eia_id. Depends on the /utilities/{slug}/geometry fix landing first so canary test can re-enable once backfill completes.