ci: preserve inbox during label migration

.github/scripts/handle-codex-pr-comments.mjs

@@ -144,9 +144,11 @@ async function getPullRequestFromInbox(prNumber) {
 }
 
 async function listInboxPullRequestNumbers() {
-  const existingIssue = chooseCanonicalInboxIssue(await findInboxIssues());
+  const inboxIssues = await findInboxIssues();
 
-  return existingIssue ? extractInboxPullRequestNumbers(existingIssue.body ?? "") : [];
+  return [
+    ...new Set(inboxIssues.flatMap((issue) => extractInboxPullRequestNumbers(issue.body ?? ""))),
+  ];
 }
 
 function extractInboxPullRequestNumbers(body) {
@@ -392,21 +394,39 @@ async function findInboxIssues() {
 }
 
 function isManagedInboxIssue(issue) {
-  return (
-    issue.title === inboxIssueTitle &&
-    issue.body?.includes(inboxMarker) &&
-    issue.labels?.some((label) => label.name === inboxIssueLabel)
-  );
+  return isLabeledInboxIssue(issue) || isMigratableInboxIssue(issue);
+}
+
+function isLabeledInboxIssue(issue) {
+  return hasInboxIdentity(issue) && issue.labels?.some((label) => label.name === inboxIssueLabel);
+}
+
+function isMigratableInboxIssue(issue) {
+  return hasInboxIdentity(issue) && isTrustedInboxIssueCreator(issue);
+}
+
+function hasInboxIdentity(issue) {
+  return issue.title === inboxIssueTitle && issue.body?.includes(inboxMarker);
+}
+
+function isTrustedInboxIssueCreator(issue) {
+  return ["app/github-actions", "github-actions[bot]"].includes(issue.user?.login);
 }
 
 function chooseCanonicalInboxIssue(issues) {
+  const openIssues = issues.filter((issue) => issue.state === "open");
+
   return (
-    issues
-      .filter((issue) => issue.state === "open")
-      .sort((left, right) => new Date(right.updated_at) - new Date(left.updated_at))[0] ?? null
+    sortIssuesByUpdatedDesc(openIssues.filter(isLabeledInboxIssue))[0] ??
+    sortIssuesByUpdatedDesc(openIssues.filter(isMigratableInboxIssue))[0] ??
+    null
   );
 }
 
+function sortIssuesByUpdatedDesc(issues) {
+  return [...issues].sort((left, right) => new Date(right.updated_at) - new Date(left.updated_at));
+}
+
 async function closeDuplicateInboxIssues(issues, canonicalIssue) {
   const closedDuplicateNumbers = [];