Add client-side rate limiting to prevent RPC endpoint abuse

[Kingsman-99]

Overview

The SDK currently fires RPC requests as fast as callers trigger them. Add a built-in token-bucket rate limiter so the SDK never exceeds the RPC provider's request quota, preventing 429 errors before they happen.

Acceptance Criteria

• StellarSplitSDK({ rateLimit: { requestsPerSecond: 10 } }) constructor option
• Token-bucket algorithm: bucket refills at the configured rate; requests block if empty
• Blocked requests queue and execute in FIFO order once tokens are available
• Queue capped at 50 pending requests; excess throws RateLimitQueueFullError
• sdk.getRateLimitStats() returns { tokensAvailable, queuedRequests, totalThrottled }
• Rate limiting disabled by default; opt-in via config
• Per-method override: sdk.getLeaderboard({ rateLimit: false }) to bypass for a single call
• Unit tests: burst of 20 calls with limit of 5/s — verify only 5 fire in the first second

[DevSolex]

@DevSolex has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi Maintainer,

I’m a smart contract and full-stack developer and would love to contribute to this issue. I’m an experienced contributor with hands-on expertise in Rust, Soroban, Cairo, and TypeScript.

I’m passionate about building secure, scalable blockchain solutions, with a strong emphasis on writing clean and maintainable code. Based on the scope of this issue, I’m confident I can deliver a complete solution within 24 hours of assignment.

I’d greatly appreciate the opportunity to contribute and help move this forward.

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

[damzempire]

@damzempire has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

i would like to work on this issue as a full stack developer

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[OpadijoIdris]

@OpadijoIdris has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Can I work on this issue?

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[ambermartin681]

@ambermartin681 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hello dear maintainer i would love to work along side you on this task sir.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @ambermartin681 to this issue.

[1sraeliteX]

@1sraeliteX has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

GM maintainer, I would like to work on this issue.

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[Caneryy]

@Caneryy has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello, can I work on this issue?

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

[grantfox-oss]

🦊 GrantFox — @ambermartin681 has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #391)
2. Your PR will be reviewed by the Stellar-split maintainers

Good luck! Track your progress on GrantFox.

[drips-wave]

Congratulations, @ambermartin681! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @ambermartin681: 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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