Summary
Problem: root CHANGELOG.md updates currently cause broad pull request and push workflow activity, including CI and workflow sanity fanout, even though changelog-only edits do not touch product, runtime, docs site, or workflow logic.
Why it matters: the PR workflow (review, prepare, and land) can add or adjust CHANGELOG.md entries while processing otherwise-ready PRs. Those changelog-only updates retrigger gates, delay landing, and create avoidable contention when several PRs are being landed close together.
What changed: CI now ignores pull requests whose only changed path is CHANGELOG.md; Workflow Sanity ignores changelog-only pull requests and main-branch pushes; Docs keeps its markdown/docs trigger but excludes root CHANGELOG.md from the push path set.
What did NOT change (scope boundary): metadata-only automation such as labelers, auto-response, real behavior proof, or external GitHub apps can still run on PR events because those workflows are event-driven rather than file-scope CI. Other markdown files, docs files, and workflow files still trigger their existing checks.
