Add SDK load balancer

[Kingsman-99]

Label: complexity: high
Points: 200

Description

The existing round-robin distribution does not account for endpoint health or response times. This issue adds an intelligent load balancer that routes requests to the fastest healthy endpoint based on rolling latency measurements.

Technical Context

Involves a new src/loadBalancer.ts. Maintain a rolling average latency per endpoint (last 10 requests). Select the endpoint with the lowest average latency for each request. Mark endpoints as unhealthy after 3 consecutive failures. Re-probe unhealthy endpoints every 30 seconds.

Acceptance Criteria

• LoadBalancer class exported from src/index.ts
• Requests routed to lowest-latency healthy endpoint
• Endpoint marked unhealthy after 3 consecutive failures
• Unhealthy endpoint re-probed after 30 seconds
• Test verifies faster endpoint receives more requests
• All existing tests pass
• TypeScript strict mode — zero any types

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[Eromosele0110]

@Eromosele0110 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I will like to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Eromosele0110 to this issue.

[drips-wave]

Congratulations, @Eromosele0110! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @Eromosele0110: 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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