Add request throttling specifically for signature verification endpoints

[Abdulazeem-code]

Description

Signature verification (Horizon lookups, crypto operations) is CPU-intensive. The general rate limiter doesn't protect against targeted abuse of these heavy endpoints.

Proposed Solution

Apply a stricter secondary rate limit (e.g., 10 requests/minute) to /register and /webhooks POST endpoints that perform signature verification.

Acceptance Criteria

• Dedicated rate limiter for signature-heavy routes
• 10 req/min limit per IP for /register and /webhooks POST
• Standard 429 response with Retry-After header
• Does not affect GET endpoints

Suggested Implementation Areas

server.js, src/routes/v1/userRoutes.js, src/routes/v1/webhookRoutes.js

Impact

Prevents CPU exhaustion attacks targeting expensive cryptographic verification operations.

[Olagoke22]

@Olagoke22 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 maintainer

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[drips-wave]

Congratulations, @Olagoke22! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

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