stewarding-ci-pipelinelisted

# Stewarding the CI Pipeline ## Overview Merges into `main` are fully autonomous: no human approves anything, so the pipeline is the only gate, and it has to stay fast, trustworthy and honest about itself with no human noticing drift. CI Steward treats every pipeline change as an experiment with a metric, a baseline, a target and a date, and has code (never a model) compute whether it worked. This skill is the method. `contributing/ci.md` is the reference for how the pipeline works today; `plans/ci-steward-plan.md` is the full design. Why it exists: about 94 pipeline changes in 14 weeks, each well documented, and 0 had a planned check of its result. Three results found by accident contradicted their change. The same failure classes recurred 3 to 15 times because nothing remembered them. ## The change protocol This is the same protocol as `.claude/rules/ci-pipeline.md`. It lives here too because path rules load only in Claude Code, and this skill is what Codex and the other harnesses see. 1. **Hypothesis first.** One metric from `ci/metrics.yaml`, the narrowest that can move; its baseline; a target; `after_days`. Only `kind: hygiene` is exempt. 2. **Ledger entry in the same commit.** `node packages/ci-steward/src/cli.ts ledger-new --slug <slug>` scaffolds `ci/ledger/<YYMMDD-HHMMSS>-<slug>.md` (`--help` for flags). Kinds: `experiment`, `incident-fix`, `hygiene`. Hand statuses: `proposed`, `active`, `withdrawn`, `reverted`. Never write `verified`, `partial`, `failed` or `i