You're deployed at a customer who needs to bulk-import contacts from a CSV their team exports by hand. The files are messy: missing fields, duplicate rows, inconsistent formats. Build an importer that validates each row, skips or reports bad rows clearly (without aborting the whole file), de-duplicates, and returns a summary of what imported and what didn't. State assumptions. AI tools are allowed. Then explain the import results to the customer's operations lead.