Use gh pr view instead of gh api for cleaner PR data fetch

Address review feedback: use the higher-level `gh pr view` command
with --json and --jq instead of constructing the raw API URL.

Author: leofang

.github/workflows/pr-metadata-check.yml

@@ -39,7 +39,8 @@ jobs:
 
           # Fetch live PR data to avoid stale event payload (race condition
           # when labels/milestone are added shortly after PR creation).
-          PR_JSON=$(gh api "repos/${GH_REPO}/pulls/${PR_NUMBER}" \
+          PR_JSON=$(gh pr view "${PR_NUMBER}" --repo "${GH_REPO}" \
+            --json assignees,labels,milestone \
             --jq '{assignees: .assignees, labels: .labels, milestone: (.milestone.title // empty)}')
           ASSIGNEES=$(echo "$PR_JSON" | jq '.assignees')
           LABELS=$(echo "$PR_JSON" | jq '.labels')