Agent Skills: merge-pr

Merge a ca PR after confirming it is genuinely ready — open, not draft (in ca a draft means the Codex-Claude review loop has not approved it), green CI, mergeable, no unresolved blocking feedback. Use once the ca loop marked the PR ready and you want it merged from the CLI. Refuses to merge drafts, red checks, or conflicts. Invoke explicitly with /ca:merge-pr.