TECH-18 · replicas ≥ 2 + readiness probe

> Product/tech item from the dimensional diagnosis (**2026-07-03, v2**, section C).

### Action
`replicas ≥ 2` + readiness probe **if** zero-downtime becomes a formal goal.

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- **Priority:** 🟢 Low
- **Epic:** #2503

The issue names no file, test, or deployment entry point. First confirm whether zero-downtime is a formal goal, then locate the relevant deployment configuration and define completion as having at least two replicas and a readiness probe when that goal is adopted.

索引モデルが issue の本文から書いたものです。