Add integration test for the creator key price history endpoint returning prices in ascending timestamp order

[Chucks1093]

Summary

The key price history endpoint should return historical price snapshots ordered oldest-first so clients can plot a chart without sorting. An integration test should seed snapshots out of order and confirm the response is always chronologically sorted.

Scope

• Seed three price snapshots at T+30m, T+10m, and T+20m (out of order)
• Call the price history endpoint and assert the response order is T+10m, T+20m, T+30m
• Assert each entry includes price, supply, and recorded_at fields
• Assert cursor pagination works correctly across pages of price history
• Assert an unknown creator returns 404

Acceptance Criteria

• Snapshots returned in ascending timestamp order
• Each entry includes price, supply, and recorded_at
• Cursor pagination correct across pages
• Unknown creator returns 404

ETA: 12 hours

---

Coordinate on Telegram