[Dmitryaf]

The simplified Kit retained everyday instructions but lost concrete engineering safeguards. Add three native Codex skills for stored data and external effects, safe code changes, and graphical user flows. Their instructions load when relevant and can be selected explicitly.

Keep existing workflow and design guidance, clarify durable project context, and document manual skill placement without restoring custom sync, profiles, manifests, or generators. Rewrite the README in plain English around purpose and use. Extend the standard-library checker to validate required skill files and minimal headers.

Validation:

• python scripts/check.py and git diff --check passed.
• Negative checks reject a wrong skill name, missing description or body, and an unavailable linked skill.
• Codex CLI 0.158.0 discovered all three enabled skills without parsing errors in repo scope and through a temporary process-level skill root. No model turns were started.
• Reviewed instruction routes for a small Python utility, a persistence change, and a new GUI; this does not prove model behavior.
• The skill-creator validator could not run without PyYAML; native Codex parsing provided format validation instead.

Existing project checkouts, global Codex instructions, and global configuration were not changed. Legacy recovery by Git SHA remains available.