fix(build): tolerate all-bench-draft instead of crashing build

src/lib/spec.ts

@@ -126,8 +126,18 @@ const loadAllBenchmarksCached = unstable_cache(
  }
  const live = benchmarks.filter((b) => b.status === "live");
  if (benchmarks.length > 0 && live.length === 0) {
- throw new Error(
- "loadAllBenchmarks: every bench draft, refusing to update cache",
+ // Previously this threw to make unstable_cache keep the previous
+ // value during a Prom blackout. The throw, however, propagates
+ // unhandled into the BUILD-time page-generation path (no previous
+ // cache there) and crashes `next build` with "Error: every bench
+ // draft". With the snapshot/KV fallback + 10s Prom timeout + cron
+ // pre-warm now in place, this safety net mostly fires during the
+ // build window of a cold deploy. Warn loudly and return the
+ // draft set — the page renders with placeholders and recovers on
+ // the next revalidate cycle. Avoids deploy crashes.
+ console.warn(
+ "[DRAFT-TRACE] all_draft slug_count=" + benchmarks.length +
+ " — Prom blackout during build/cold-start, returning placeholders",
  );
  }
  return benchmarks.sort((a, b) => a.number.localeCompare(b.number));