Sync descriptions and issues, run workflows nightly

mirror.js now keeps repo descriptions in step with GitHub. A new
sync-issues workflow copies issues, PR conversations and comments onto
the mirrors with GitHub's numbering. Shared API helpers move to
gitea-mirrors.js. Every workflow now runs once a night, 1.5 hours apart.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

gitea-mirrors.js

@@ -0,0 +1,69 @@
+const { GH_PAT, GITEA_TOKEN, GITEA_URL } = process.env;
+if (![GH_PAT, GITEA_TOKEN, GITEA_URL].every(Boolean)) {
+  throw new Error('GH_PAT, GITEA_TOKEN, and GITEA_URL are required');
+}
+
+const gitea = `https://${GITEA_URL.replace(/^https?:\/\//, '').replace(/\/$/, '')}/api/v1`;
+const github = 'https://api.github.com';
+const ghHeaders = { Authorization: `token ${GH_PAT}`, Accept: 'application/vnd.github+json' };
+const gtHeaders = { Authorization: `token ${GITEA_TOKEN}`, 'Content-Type': 'application/json' };
+const key = value => value.toLowerCase();
+const enc = (...parts) => parts.map(encodeURIComponent).join('/');
+
+const request = async (url, headers, method = 'GET', body, missingOK = false) => {
+  const res = await fetch(url, {
+    method, headers, body: body && JSON.stringify(body), signal: AbortSignal.timeout(30_000)
+  });
+  if (res.status === 404 && missingOK) return null;
+  if (!res.ok) throw new Error(`${method} ${url}: ${res.status} ${(await res.text()).slice(0, 300)}`);
+  return res.status === 204 ? null : res.json();
+};
+
+const pages = async (url, headers, sizeKey, missingOK = false) => {
+  const all = [];
+  for (let page = 1; page <= 1000; page++) {
+    const next = new URL(url);
+    next.searchParams.set(sizeKey, '100');
+    next.searchParams.set('page', String(page));
+    const batch = await request(next, headers, 'GET', null, missingOK);
+    if (batch === null) return null;
+    if (!Array.isArray(batch)) throw new Error(`Expected an array from ${next}`);
+    if (!batch.length) return all;
+    all.push(...batch);
+  }
+  throw new Error(`Pagination limit reached for ${url}`);
+};
+
+const source = repo => {
+  try {
+    const url = new URL(repo.original_url.replace(/^git@github\.com:/i, 'https://github.com/'));
+    const parts = url.pathname.replace(/\.git\/?$/i, '').split('/').filter(Boolean);
+    return url.hostname === 'github.com' && parts.length === 2 ? { owner: parts[0], name: parts[1] } : null;
+  } catch {
+    return null;
+  }
+};
+
+// Pull mirrors of GitHub repos owned by the Gitea user or its orgs.
+// Frozen mirrors (sync interval 0, e.g. renamed -goneN ones) are left out.
+const listMirrors = async () => {
+  const [gtUser, gtOrgs] = await Promise.all([
+    request(`${gitea}/user`, gtHeaders),
+    pages(`${gitea}/user/orgs`, gtHeaders, 'limit')
+  ]);
+  const owners = [gtUser.login, ...gtOrgs.map(org => org.username || org.name)];
+  const ownerKeys = new Set(owners.map(key));
+  const repos = (await Promise.all(owners.map((owner, i) =>
+    pages(i ? `${gitea}/orgs/${enc(owner)}/repos` : `${gitea}/user/repos`, gtHeaders, 'limit')
+  ))).flat();
+  return [...new Map(repos.map(repo => [repo.id, repo])).values()]
+    .filter(repo => repo.mirror && repo.original_url && !repo.archived && repo.mirror_interval !== '0s')
+    .filter(repo => ownerKeys.has(key(repo.owner.login)))
+    .map(repo => ({
+      repo, gh: source(repo), name: `${repo.owner.login}/${repo.name}`,
+      gtRepo: `${gitea}/repos/${enc(repo.owner.login, repo.name)}`
+    }))
+    .filter(mirror => mirror.gh);
+};
+
+module.exports = { github, ghHeaders, gtHeaders, enc, request, pages, listMirrors };