Improvement: create a new CSV parser or update the current one to support input with a header row

The current CSVParser class is not designed to properly handle input if it contains a header row.
We should either subclass this parser or create a new one that can handle parsing of csv input that contains a header row. This parser should probably also try to validate the header to ensure the values match the keys we expect to receive. Python's `csv.DictReader` can likely be used for this, or we may be able to convert the CSVParser to strictly use `csv.DictReader` instead of adding a new class (will need to investigate more...)

Start by locating the CSVParser class and reading how current CSV input is consumed. Compare Python's csv.DictReader with the existing behavior, then define whether to extend or replace the parser and how expected headers are validated; done means header-row input parses correctly and invalid headers are rejected, with focused tests added around those cases.

Written by the indexing model from the issue text.