feat(ci): granular status updates for reth-bench workflow (#22297)

Co-authored-by: Amp <amp@ampcode.com>

.github/scripts/bench-update-status.js

@@ -0,0 +1,27 @@
+// Updates the reth-bench PR comment with current status.
+//
+// Reads from environment:
+//   BENCH_COMMENT_ID  – GitHub comment ID to update
+//   BENCH_JOB_URL     – URL to the Actions job page
+//   BENCH_CONFIG      – Config line (blocks, warmup, refs)
+//   BENCH_ACTOR       – User who triggered the benchmark
+//
+// Usage from actions/github-script:
+//   const s = require('./.github/scripts/bench-update-status.js');
+//   await s({github, context, status: 'Building baseline binary...'});
+
+function buildBody(status) {
+  return `cc @${process.env.BENCH_ACTOR}\n\n🚀 Benchmark started! [View job](${process.env.BENCH_JOB_URL})\n\n⏳ **Status:** ${status}\n\n${process.env.BENCH_CONFIG}`;
+}
+
+async function updateStatus({ github, context, status }) {
+  await github.rest.issues.updateComment({
+    owner: context.repo.owner,
+    repo: context.repo.repo,
+    comment_id: parseInt(process.env.BENCH_COMMENT_ID),
+    body: buildBody(status),
+  });
+}
+
+updateStatus.buildBody = buildBody;
+module.exports = updateStatus;