Add integration test for creator detail including price_change_24h field in response

[Chucks1093]

Summary

The creator detail response must include a price_change_24h field sourced from the price snapshot table. An integration test should confirm the field is present and correctly signed (positive for increase, negative for decrease).

Scope

• Seed a creator with a current price higher than the 24h ago snapshot
• Call GET /creators/:id and assert price_change_24h is a positive number
• Seed a creator with a lower current price and assert price_change_24h is negative

Acceptance Criteria

• Positive change returns a positive price_change_24h value
• Negative change returns a negative price_change_24h value
• Field is always present in the response

ETA: 12 hours

---

Coordinate on Telegram