chore(release): add yarn release:refs helper to list release refs

Since workflow_dispatch dropdowns can't be populated from git history, this
prints recent release (version) commits so a maintainer can copy a real release
ref to nominate for the release workflow's `ref` input.

Implemented as release-refs.mjs (matching collectCoverage.mjs). It anchors the
grep to the exact release subjects (stable + rc) so reverts, merge commits and
other commits that merely mention the phrase don't leak in, and annotates each
ref with the @cardano-sdk/core version it carries as a quick anchor to confirm
a ref's versions before nominating it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: rhyslbw

package.json

@@ -36,6 +36,7 @@
     "version:stable": "lerna version --conventional-graduate --allow-branch master --create-release github -m \"ci: publish packages [skip actions]\" --sign-git-commit",
     "publish:rc": "lerna publish from-package --dist-tag rc --yes",
     "publish:stable": "lerna publish from-package --yes",
+    "release:refs": "node release-refs.mjs",
     "test": "yarn workspaces foreach -v run test",
     "test:build:verify": "yarn workspaces foreach -v run test:build:verify",
     "test:e2e": "yarn workspaces foreach -v run test:e2e",

release-refs.mjs

@@ -0,0 +1,30 @@
+// Lists recent release (version) commits with the @cardano-sdk/core version each carries,
+// so a maintainer can nominate a real release ref (and its versions) for the `release`
+// workflow's `ref` input. workflow_dispatch dropdowns can't be populated from git history,
+// so this is the discovery aid. See .github/workflows/release.yaml.
+import { execSync } from 'node:child_process';
+
+// Anchored to the exact release subjects (stable + rc) so reverts, merges and other commits
+// that merely mention the phrase don't leak in.
+const pattern = '^ci: publish (rc )?packages \\[skip actions\\]$';
+const limit = Number.parseInt(process.argv[2], 10) || 20;
+
+const log = execSync(`git log -E --grep='${pattern}' --format='%h|%H|%ci' -n ${limit}`, {
+  encoding: 'utf8'
+}).trim();
+
+if (!log) {
+  console.log('No release commits found.');
+  process.exit(0);
+}
+
+for (const line of log.split('\n')) {
+  const [short, full, date] = line.split('|');
+  let version = '?';
+  try {
+    version = JSON.parse(execSync(`git show ${full}:packages/core/package.json`, { encoding: 'utf8' })).version;
+  } catch {
+    // packages/core/package.json may not exist at very old commits — leave as '?'
+  }
+  console.log(`${short}  core@${version.padEnd(11)}${date}`);
+}