docs: add CONTRIBUTING.md and AGENTS.md

[BigLep]

Summary

• Added CONTRIBUTING.md with contribution guidelines covering:
  • Conventional commits for all commits and PR titles
  • GitHub issue references in PR descriptions
  • Visual evidence (screenshots/terminal output) for user-facing changes
  • Draft PR workflow
  • Code quality standards (concise comments, self-documenting code)
• Added AGENTS.md to ensure AI coding tools follow the contribution guidelines

🤖 Generated with help from Claude Code

[Copilot]

Pull Request Overview

This PR establishes contribution guidelines and AI agent standards for the repository by adding two new documentation files.

• Added CONTRIBUTING.md with comprehensive contribution guidelines including conventional commits, issue references, visual evidence requirements, and code quality standards
• Added AGENTS.md to ensure AI coding tools follow the contribution guidelines

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
CONTRIBUTING.md	Establishes project contribution standards covering commit conventions, PR requirements, and code quality expectations
AGENTS.md	Directs AI coding assistants to follow the contribution guidelines defined in CONTRIBUTING.md

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[BigLep]

This came about for me when assigning @copilot to take on easy issues that were opened. It wasn't following conventional commits and I don't want to have to clean up after the "agents" going forwards...

[SgtPooki]

LGTM.. AGENTs or CONTRIBUTING could be fleshed out further to provide better context of the goals of the project too:

1. reference implementation: stay away from wide optionality and use opinionated best practices, explaining why we did things a certain way. (AI creating PRs automatically should require us to fill out areas where there is ambiguity)
2. everything should be documented well: it's a learning resource

[rvagg]

AGENTS.md need a bit more work, it should be instructions for agents, not about how to use agents, since these typically end up in contexts. But I'll follow up on that, I'm just in the process of cleaning up the Synapse one, I'll come back here and do the same