Ult Onboarding Index

Discover CEP-managed content already present in a target repo (What/How layer docs, compiled guidelines, context packages, decision ledger) via existence checks against layout-slots-registry.yaml-resolved paths, then write one canonical root AGENTS.md onboarding index plus thin per-tool pointer stubs (.github/copilot-instructions.md, CLAUDE.md, .cursor/rules/onboarding.mdc) that link into it. All writes are marked-block or existence-gated and non-destructive, including install.sh's own AGENTS.md skill-catalog block. Codex needs no separate stub -- root AGENTS.md is already its native onboarding format. Do NOT use it to generate the CEP content itself (ult-autoscaffold-con…