core: retry/sleep boilerplate duplicated across deploy, post-deploy and upgrade

[Dione-b]

Summary

Retry/sleep boilerplate is copy-pasted across the contract operation layer:

• sleep reimplemented in artifacts/artifacts-lock.ts:7-11, contracts/deploy-contract.ts:51-55, contracts/run-post-deploy.ts:42-46, contracts/upgrade-contract.ts:52-56
• The full retry loop with retryDelaysMs/maxAttempts/onTransientRetry is duplicated in deploy-contract.ts:~160-210, run-post-deploy.ts:~190-235, and upgrade-contract.ts:~120-165

Why it matters

Retry semantics (delay fallback, callback handling, last-attempt behavior) are defined three times and have already diverged (see the unguarded-callback inconsistency in #M6).

Suggested fix

Extract a small withRetries({ attempts, delays, isRetryable, onRetry, fn }) helper, keep per-call retryDelaysMs overrides, and reuse it in all three loops plus the artifacts lock wait.

Priority: Medium | Release impact: Patch | Breaking: No

[rexx010]

@rexx010 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello Maintainer, I have experience in open source and web development, please can you assign to me this issue I applied?.
I will implement the task perfectly.
And I will ensure to follow the requirements and guideline you have given.
Thanks much.

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[Galmanus]

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

PR #196. The retry loop and its sleep helper were copied across deploy, upgrade and post-deploy, and had already drifted apart. The fix pulls them into one shared helper used by all three. Covered by a test; full core suite passes.

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