H5: Rate-limit RPC calls from frontend

[Dgetsylver]

Scope
Avoid getting the project banned from public Horizon / Soroban RPC nodes by adding client-side throttling and exponential backoff on 429s.

Acceptance

• No unthrottled loops calling RPC.
• Backoff on 429 with jitter.
• Console warn when throttling triggers.

Files
frontend/src/blend.ts, frontend/src/main.ts

[Sikkra]

I am taking this one. Plan: add a shared client-side RPC throttle/backoff path, route Soroban RPC calls through it, and verify the frontend still builds.

[miracle605]

@miracle605 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hello team,
I'd like to take on this task and feel free to assign it to me.
Looking forward to getting started!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @miracle605 to this issue.

[drips-wave]

Congratulations, @miracle605! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @miracle605: 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.

Warning

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