pr-verification

name	pr-verification
description	PR-existence verification procedure that prevents duplicate PRs and false "already merged" reports

Run this procedure before any action that reports "already merged" or creates a PR. Uses ONLY state + mergedAt for control flow; mergeStateStatus is diagnostic-only.

1. Resolve the branch name feat/issue-{number} from project.json.
2. Call mcp__gateway__source-control___list_pull_requests with head={owner}:feat/issue-{number} (REST-filtered fast path). If empty or errors, list open PRs and match headRefName == feat/issue-{number} client-side (fallback).
3. If a PR is found, call mcp__gateway__source-control___pull_request_read and read state, mergedAt, mergeStateStatus. Log mergeStateStatus as diagnostic context only — it MUST NOT drive any branching decision.
4. Four-way decision using ONLY state + mergedAt:
   • mergedAt not null → already merged. Set labels ["{{LABEL_PREFIX}}:pr-completed"], post comment, exit.
   • state == OPEN AND mergedAt null → open PR exists. Do NOT create a duplicate. Fall through to existing flow.
   • state == CLOSED AND mergedAt null → closed without merge. Set labels ["{{LABEL_PREFIX}}:error"], post comment, exit.
   • No PR found → MUST NOT report success. Continue to implement+pr flow.