Add SDK evolution upgrade commands

[ebarti]

Summary

• Add a checked-in Claude slash command for running the local SDK evolution upgrade workflow.
• Add a checked-in Codex skill that invokes the same agent-runtime-kit SDK evolution workflow.
• Document the required safeguards: fresh worktree, report-only pass before implementation, freshness cutoff bypassing, runtime-backed AI stages, behavior/API/release-note evidence gates, recursive self-adaptation checks, draft PR creation, and no auto-merge or release publishing.

Validation

• git diff --check
• env -u UV_EXCLUDE_NEWER -u UV_EXCLUDE_NEWER_PACKAGE uv run --with pyyaml python /Users/eloibarti/.codex/skills/.system/skill-creator/scripts/quick_validate.py .codex/skills/agent-runtime-kit-upgrade
• env -u UV_EXCLUDE_NEWER -u UV_EXCLUDE_NEWER_PACKAGE uv run python -m examples.sdk_evolution_agent --help
• env -u UV_EXCLUDE_NEWER -u UV_EXCLUDE_NEWER_PACKAGE uv run ruff check .