A claim across a row, cache and queue needs undo

// claim → side effects → on failure, put the durable row back first
const won = await db.update(runs).set({ status: "running" })
  .where(and(eq(runs.id, id), ownedByCaller(), eq(runs.status, "waiting")));
if (!won) return { resumed: false };
try { await cache.save(state); await queue.publish(step); }
catch (e) { await retry(() => revertToWaiting(id)); await cache.restore(prev); throw e; }