Spec: Async jobs

Postgres-backed jobs on Drizzle. Skip Redis unless asked (npx skills add redis/agent-skills@redis-core).

Follow .agents/skills/add-async-jobs/SKILL.md.

Shape

• jobs table in db/schema.ts
• lib/jobs/enqueue.ts
• scripts/worker.ts with FOR UPDATE SKIP LOCKED
• No BullMQ “for later”