{"status":"ok","message":"Sustainable Facility Intelligence API","endpoints":{"GET    /api/data":"Latest sensor snapshot","GET    /api/data?all=true":"All records (newest first)","GET    /api/data?limit=N":"Last N records","GET    /api/data/:id":"Single record by ID","POST   /api/data":"Create new sensor snapshot","PUT    /api/data":"Update latest sensor snapshot directly","PUT    /api/data/:id":"Update sensor snapshot by ID","DELETE /api/data/:id":"Delete single record","DELETE /api/data":"Delete ALL records"}}