Update all documentation files to use 'atlas' instead of 'orchestrator-sisyphus'. AGENTS.md, src/agents/AGENTS.md, docs/features.md, docs/guide/overview.md all updated. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>