Pipeline Retro

Purpose

Close the self-improvement loop for the pipeline generator. When pipeline-test-runner reports failures, this skill traces each failure to its root cause in the generation chain, proposes fixes at the generator level (not the artifact level), then regenerates and re-tests to prove the fix works.

This skill implements the Three-Layer Pattern from adr/self-improving-pipeline-generator.md:

Layer 1: ARTIFACT -- Fix the specific generated skill
  -> SKIP (teaches the system nothing; the fix dies with this one pipeline)

Layer 2: GENERATOR -- Fix the rules, templates, chain composition, or step menu
  -> DO (root cause fix that propagates to ALL future pipelines)

Layer 3: VALIDATION -- Regenerate the affected skills + re-test
  -> PROVE (empirical evidence the fix actually works end-to-end)