Add cold-start continuity proof

[uncfreak1255-code]

Summary

• add one active adaptive-harness candidate plan as the durable next-work source
• add thin repo-local restart instructions without hooks or permanent agents
• add deterministic contract tests and an ephemeral read-only Codex cold-start smoke

Proof

• npm test
• npm run smoke:cold-start
• git diff --check HEAD^ HEAD
• Codex autoreview: clean after one accepted trace-verification fix
• pre-landing review: no issues found

The post-commit smoke recovered source 71eef8e33ac8ffb5d70b06fa332f3c0556a4ef0b, the frozen v0.2.0 baseline, rejected global promotion, the adaptive-harness receipt eval, all proof commands, and the protected-main boundary. Its trace proved reads of AGENTS.md, both plans, the dogfood report, and Git HEAD.

Boundaries

This does not change skills/loopspine/SKILL.md, install globally, add hooks, or claim the adaptive-harness candidate is proven.