CSV-to-JSON final check: validate headers and types

After converting CSV to JSON, confirm that the first row became the intended keys and that output object count matches data rows. Inspect quoted commas, embedded newlines, blank cells, leading-zero IDs, dates, and large numbers. CSV cells begin as text; automatic type inference can change meaning. Parse the output as JSON and compare representative records with the source CSV. A syntactically valid array is not enough if keys or values were misread.