Add integration test for the creator key supply endpoint returning the correct supply after a sequence of buys and sells

[Chucks1093]

Summary

The creator key supply endpoint should always reflect the current on-chain supply. An integration test should drive a sequence of buys and sells and confirm the endpoint returns the correct supply at each step without serving a stale cached value.

Scope

• Seed a creator with initial supply 0
• Buy 10 keys and assert the supply endpoint returns 10
• Buy 5 more keys and assert supply is 15
• Sell 8 keys and assert supply is 7
• Sell the remaining 7 keys and assert supply is 0
• Assert the supply endpoint reflects the updated value within one request (no stale cache served)

Acceptance Criteria

• Supply 10 after first buy
• Supply 15 after second buy
• Supply 7 after selling 8
• Supply 0 after selling the remainder
• No stale cached value returned between operations

ETA: 12 hours

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Coordinate on Telegram

[Gentleslyl2006]

Hello maintainer
If this issue get assigned to me. You're guaranteed perfect results in return. I can fix it