Update to Caveman

{
  "name": "lean-build",
  "description": "Use when implementing a feature or change and the work should be reduced to the smallest coherent, testable slice.",
  "included_files": [
    {
      "relative_path": "agents/openai.yaml",
      "size_in_bytes": 260
    }
  ],
  "skill_md_contents": "---\nname: lean-build\ndescription: Use when implementing a feature or change and the work should be reduced to the smallest coherent, testable slice.\n---\n\n# Lean build\n\nNative Core's architecture-first simplicity remains mandatory. Turn feature into complete narrow outcome fitting system.\n\n- Derive observable acceptance and explicit non-goals from request and repository.\n- Trace entry point through layers owning invariants.\n- Deliver coherent end-to-end path across responsible layers; never force work into one file, direct expression, or local patch.\n- Reuse fitting seam. Refactor when patching duplicates behavior, weakens ownership, or hides root cause.\n- Omit modes, providers, config, extensibility, and polish unless acceptance needs them.\n- Add surface, dependency, service, config, or migration only for lifecycle design or acceptance; state material tradeoff.\n- Keep work runnable; preserve Core safety.\n\nExercise path. Run focused proof. Stop when acceptance passes. Report only material omissions and trigger.\n"
}