switchbot-webhook OK.
POST /            SwitchBot webhook target
GET  /list         raw KV events
GET  /errors      D1 INSERT errors
GET  /readings    ?device=MAC | ?facility=slug | (all) &limit=N
GET  /latest      latest per device (with facility mapping)
GET  /devices     mapping list
POST /devices     upsert mapping
POST /backfill   KV evt:* -> D1 (idempotent)