Add an auction state endpoint returning the current auction config and sold count for a creator key

[Chucks1093]

Summary

The creator dashboard auction panel needs to read the current auction state. A GET /keys/:keyId/auction endpoint that returns the configured auction price, supply, and sold count from the contract should be added.

Scope

• Add GET /keys/:keyId/auction endpoint (no auth required)
• Return auctionPrice, auctionSupply, auctionSold, and auctionStatus (not_configured, active, completed)
• Read auction state from persistent contract storage via the Soroban RPC
• Cache the response in Redis for 30 seconds and invalidate after each auction buy
• Return 404 for unknown key IDs

Acceptance Criteria

• auctionPrice, auctionSupply, and auctionSold returned correctly
• auctionStatus computed correctly for each state
• not_configured returned when no auction is set up
• Cache invalidated after each auction buy
• 404 returned for unknown key ID

ETA: 12 hours

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Coordinate on Telegram

[Netty-kun]

@Netty-kun has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer, I have read and understood the issue requirements and checked the necessary documentation. I’m confident I can work on this task effectively and deliver a proper solution.
Happy to discuss the approach first if that's useful before I start.

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[KingDavid9999]

@KingDavid9999 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer, I'd very much appreciate the opportunity to work on this issue.
Having reviewed the acceptance criteria, I'm confident that I'd be able to have a PR up shortly after being assigned.
Kindly assign this issue to me.
Thank you!

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[devJaja]

@devJaja has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

can I work on this please

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Congratulations, @devJaja! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

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