Create AGENTS.md with agent instructions

[bmos]

Added comprehensive agent instructions covering scope, sources of truth, handling ambiguity, pre-commit guidelines, change discipline, and decisionmaking authority.

Based on the PyPDFForm AGENTS.md file.

What is this change?

• AI-created pull requests are becoming more frequent, often ignoring pull request templates and project coding standards. Many projects are implementing AI policies to encourage, regulate, or ban the use of AI in coding and/or submission workflows. Along with including reference to the policy in contributor guides, AGENTS.md can be used to help agents follow our best practices and avoid spam, without disallowing the use of AI assistance.

Considerations for discussion

• Are there other standards / guidelines we should be enforcing?
• Is there support in the parsons project for requiring humans to write pull requests?
• Do parsons contributors want to allow the use of AI coding agents?

How to test the changes (if needed)

• Ask an agent to implement a change to our repo, with this branch checked out.

Breaking Changes

Breaking changes are changes to our public API which may require existing users to change their code. If there are no breaking changes, any existing parsons user should not need to do anything after updating their parsons version.

Does this PR introduce breaking changes?

• label: Breaking change — This PR introduces one or more breaking changes.
• label: Non-breaking change — This PR does not introduce one or more breaking changes.

Details (if needed)

• (List out any changes to the API that may cause breaks for developer implementation.)

[shaunagm]

This seems like it deserves more of a community discussion. I know you're not generally available during Parsons Parties, do you want to coordinate a separate time to have a discussion?

[bmos]

I can schedule myself to be available, maybe next Thursday?

[shaunagm]

The 10th? That works for me

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.