Development environment setup

[masnwilliams]

Add AGENTS.md to document Cursor Cloud-specific development environment gotchas and instructions for future agents.

---

  

---

Note

Low Risk
Documentation-only change with no impact on runtime behavior or security.

Overview
Adds a new AGENTS.md runbook documenting Cursor Cloud-specific development setup, including common build/test commands, Docker-in-Firecracker requirements, and operational gotchas (e.g., UKC_METRO usage, CDP proxy behavior, recorder restart limitations, image naming/quota, e2e image env vars, and required Go version).

^{Written by Cursor Bugbot for commit 71a8478. This will update automatically on new commits. Configure here.}

[cursor]

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
_{Learn more about Cursor Agents}