Add Known Limitations section to AGENTS.md documenting:
- AMD GPU not implemented (use NVIDIA, Apple Silicon, or CPU)
- 100+ node gang allocation stress testing not yet implemented
- Podman-in-Docker CI requires privileged mode, not yet automated
- Error handling patterns for unimplemented features
- Container usage rules (Docker for testing/deployments, Podman for experiments)
- Error codes table (NOT_IMPLEMENTED, NOT_FOUND, INVALID_CONFIGURATION)
Update testing documentation to reflect new test locations:
- Unit tests moved from tests/unit/ to internal/ (Go convention)
- Update all test file path references in security testing docs