[Soroban] Add Royalty Support

[Eniola3321]

Add configurable royalty support using basis points (BPS).

Background

Creators should receive royalties on secondary sales, while the platform may receive a configurable fee.

Pasted text.txt

Document

Tasks
Add set_royalty().
Store royalty recipient.
Validate max 1500 BPS.
Add royalty getter.
Support platform fee.
Swagger / API Integration
Document:

GET /nfts/:id/royalty

PATCH /nfts/:id/royalty

Add response schema.
Acceptance Criteria

Royalties are stored correctly.

Values above 15% are rejected.

Getter returns recipient and BPS.

[Aj-Kayvee]

@Aj-Kayvee has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi, please I would love to resolve this issue

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[oyebolarotimi269-ai]

@oyebolarotimi269-ai has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

please assign this issue to me 🥺🙏.

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[davismas23]

@davismas23 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I would love to resolve this issue

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[HassanKorey]

@HassanKorey has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi maintainer, Kindly assign me this issue.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @HassanKorey to this issue.

[drips-wave]

Congratulations, @davismas23! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

🧑‍💻 @davismas23: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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