chore: import upstream snapshot with attribution

.github/scripts/check_team_membership.js

@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+/**
+ * Resolve the issue author and check their team membership.
+ *
+ * @param {object} opts
+ * @param {object} opts.github - Octokit REST client from actions/github-script
+ * @param {object} opts.context - GitHub Actions context
+ * @param {object} opts.core - GitHub Actions core toolkit
+ * @param {string} opts.teamSlug - Team slug to check membership against
+ * @param {string|number} opts.issueNumber - Issue number to resolve author for
+ * @returns {Promise<{author: string|null, isTeamMember: boolean}>}
+ */
+async function checkTeamMembership({ github, context, core, teamSlug, issueNumber }) {
+  let author = context.payload.issue?.user?.login;
+  if (!author) {
+    const { data: issue } = await github.rest.issues.get({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      issue_number: Number(issueNumber),
+    });
+    author = issue.user?.login;
+  }
+
+  if (!author) {
+    core.setFailed('Could not determine issue author (user may be deleted).');
+    return { author: null, isTeamMember: false };
+  }
+
+  try {
+    await github.rest.teams.getByName({
+      org: context.repo.owner,
+      team_slug: teamSlug,
+    });
+  } catch (error) {
+    core.setFailed(`Team lookup failed for ${teamSlug}: ${error.message}`);
+    throw error;
+  }
+
+  let isTeamMember = false;
+  try {
+    const teamMembership = await github.rest.teams.getMembershipForUserInOrg({
+      org: context.repo.owner,
+      team_slug: teamSlug,
+      username: author,
+    });
+    isTeamMember = teamMembership.data.state === 'active';
+  } catch (error) {
+    if (error.status === 404) {
+      core.info(`Author ${author} is not a member of team ${teamSlug}.`);
+      isTeamMember = false;
+    } else {
+      core.setFailed(`Team membership lookup failed for ${author}: ${error.message}`);
+      throw error;
+    }
+  }
+
+  return { author, isTeamMember };
+}
+
+module.exports = checkTeamMembership;