Initialize AGENTS.md

Set up AI agent documentation and machine-readable config for this project.

Architecture: AGENTS.md (human guidance) + .agents.yml (machine config) + CLAUDE.md (symlink)

Step 1: Generate AGENTS.md

Check existing state first: !${CLAUDE_PLUGIN_ROOT}/skills/init/scripts/check-existing.sh

If AGENTS.md exists, ask: Regenerate | Enhance | Skip

Then invoke the hierarchical agents skill:

Skill(skill: "hierarchical-agents")

Complete all 4 phases: Repository Analysis → Root AGENTS.md → Sub-folder files → Special Considerations