NYC Housing Preservation & Development (HPD) violations — every notice of violation issued at a multi-family building. Search by `bbl` (10-digit) or `address` (street_name substring). Filter by `classCode` (A=least severe, B=hazardous, C=immediately hazardous) and `currentStatusOnly=true` to limit to open violations. Each row carries violation id, building id, full address + apartment + story, inspection + approved + certify-by + correct-by dates, current status + status date, and the narrative NOV description. Use for landlord-history, code-enforcement, and tenant-rights agents.