Add retry logic with exponential backoff for Stellar RPC errors

[sshdopey]

What

sendTransaction and getTransaction calls in src/lib/stellar.ts have no retry-on-network-error logic. Transient failures (timeout, 503, network blip) cause immediate transaction failure.

Why

Stellar RPC endpoints can experience transient failures. Without retries, a single network hiccup causes a transaction to fail even though it may have succeeded on-chain.

Scope

• Add retry wrapper for Stellar RPC calls
• Exponential backoff with jitter
• Configurable max retries and base delay
• Only retry on transient errors (timeout, 503, network error)
• Do NOT retry on permanent errors (400, 422)

Acceptance Criteria

• RPC calls retry on transient errors (up to RPC_MAX_RETRIES)
• Exponential backoff with jitter between retries
• Base delay configurable via RPC_RETRY_BASE_MS
• Permanent errors are not retried
• Logs each retry attempt

Technical Context

• src/lib/stellar.ts:34 — sendTransaction
• src/lib/stellar.ts:43 — getTransaction
• src/lib/registry.ts:53 — simulateTransaction
• New env vars: RPC_MAX_RETRIES (default: 3), RPC_RETRY_BASE_MS (default: 1000)

[Mistersmile4585]

@Mistersmile4585 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I'm a Full Stack Software Engineer with experience building scalable web and mobile applications. I enjoy solving problems, learning quickly, and contributing to meaningful projects. I will be glad if this issue is assigned to me

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Congratulations, @Mistersmile4585! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

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