Add a holder registry endpoint returning each holder's balance split into liquid and staked quantities

[Chucks1093]

Summary

The updated holders table needs a stakedQuantity field per holder. The existing holders endpoint should be extended to include stakedQuantity and liquidQuantity derived from the staking_positions contract state.

Scope

• Extend GET /keys/:keyId/holders to include stakedQuantity and liquidQuantity per holder
• Fetch staking positions from the staking_positions persistent map for each holder via the Soroban RPC
• Compute liquidQuantity as totalQuantity minus stakedQuantity
• Cache individual holder staking positions in Redis for 30 seconds
• Maintain backward compatibility by adding the new fields without removing existing ones

Acceptance Criteria

• stakedQuantity and liquidQuantity present on every holder record
• liquidQuantity correctly computed as total minus staked
• Holders with no stake show stakedQuantity of 0
• Redis cache used for staking position reads
• Existing fields unchanged for backward compatibility

ETA: 12 hours

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Coordinate on Telegram

[devzakari-sketch]

Hi maintainer can i work on this task

[Akinloluwa20]

@Akinloluwa20 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I would like to work on this issue

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[Bobai100]

@Bobai100 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi Maintainer,
I’d really appreciate the opportunity to work on this issue. Having reviewed the acceptance criteria, I’m confident that I can submit a PR after being assigned.
Please 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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[drips-wave]

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

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[devJaja]

Closed by PR #859 — holder registry with staked/liquid balance implemented.

[devJaja]

Closed by PR #859