Add Agentsor File Contracts

[linkoinsight]

What changed

Adds Agentsor File Contracts to the CSV tools list. It is an MIT-licensed command-line tool for validating completed CSV and Parquet files against a TOML contract.

Disclosure: I maintain the submitted project.

Why it fits

The CSV reader supports standard field quoting through PyArrow and the tool validates schema, types, row and byte bounds, and optional freshness.

Validation

• Rendered the README successfully from data/projects.toml
• git diff --check passes

[dbohdan]

Good premise, but this project was started yesterday. I have a policy against adding brand-new projects because they are likely to be abandoned. I'll put this PR on hold. Please ping me if the project is still maintained in six months.