ab2f574ff3
When a commit fixes a bug introduced by an identifiable prior commit, the fix should record the offending short SHA in a Regression-of: trailer at the bottom of the commit message body. This is a standard Git trailer (parseable by git interpret-trailers) that makes intra-release regression detection trivial: the release skill can now read the trailer directly instead of hunting through git log and git blame to figure out whether a 'Fixed' entry actually describes a bug a shipped user ever saw. - AGENTS.md: new 'Attributing Regressions' subsection under Using Git with the convention, when-to-add/skip rules, and tracing tips. - .agents/skills/release/SKILL.md: Step 5.2 now has a fast path that reads Regression-of trailers via 'git log --format=%(trailers:...)', with the existing manual git log/blame approach as fallback. - CONTRIBUTING.md: brief mention in the Bug fixes section and a new self-review checklist item pointing at AGENTS.md.