CSV-to-JSON handoff: define the schema explicitly

A clean handoff includes the source CSV, resulting JSON, delimiter and encoding, header mapping, output object count, and type policy. Explain whether blank cells become empty strings, nulls, or omitted keys. Mark columns such as IDs and postal codes that must remain strings. If there were malformed rows, state how they were handled instead of silently dropping them. A downstream consumer should not need to infer the schema from one lucky record.