Fix an Overly Broad Retry Predicate That Can Retry Permanently-Failed Lookups Forever

[Emmyt24]

Description

backend/src/stellar-service-integration/rate-limiter.ts's isRetryableError treats any error whose message contains both "not found" and "transaction" as retryable, which also matches a genuinely nonexistent or typo'd transaction hash — that lookup gets retried up to the configured max attempts and backoff for no reason.

Requirements and Context

• Narrow the predicate to only match the specific transient not-found condition it's meant for
• Do not regress the genuinely transient case (a real transaction not yet indexed)

Suggested Execution

Branch: fix/integration-retryable-error-predicate

Implement Changes

• Narrow the predicate to only match the specific transient not-found condition it's meant for (e.g. by error code/type rather than a substring match on the message)
• Add a test asserting a permanently-invalid transaction hash lookup does not get retried the full attempt budget
• Add a test asserting the genuinely transient case (not yet indexed) still retries as before

Test and Commit

Run npx vitest run src/stellar-service-integration/__tests__ — a permanently-invalid transaction hash fails fast while a genuinely transient not-found still retries.

Example Commit Message

fix(backend): narrow the retryable-error predicate for transaction lookups

Closes #<issue>

Guidelines

• Branch from main, open a PR back to main
• All new code must have corresponding tests
• Run npm run lint and npm run test before pushing
• Follow existing naming conventions and file structure
• PR description must reference this issue number (e.g., Closes #<issue>)
• Keep commits atomic and use conventional commit format

[whiteghost0001]

@whiteghost0001 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi! I'm a full-stack developer with experience building modern web applications using JavaScript/TypeScript, React, Next.js, Node.js, and blockchain technologies such as Stellar. I enjoy working on open-source projects, writing clean, maintainable code, and collaborating with the community.

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