fix(soroban): fix off-by-one key extraction in listStorageKeys

[shobhamerabacha-star]

Summary

This PR resolves an off-by-one error in ContractStateService.listStorageKeys() where parts[3] was returning the cache entry's durability instead of the actual storage key. It also adds warning logging when individual key reads fail during exportContractState() and provides full unit test coverage.

Changes Made

1. Storage Key Indexing & Structure (src/modules/stellar/soroban/contract-state.service.ts):

   • Cache key format: soroban:state:{contractId}:{durability}:{keyPart}.
   • Updated listStorageKeys() to check parts.length >= 5 and extract parts.slice(4).join(':'), ensuring storage keys with colons are fully preserved.
   • Retained raw key as fallback when the key does not match standard segment counts.

2. Failure Logging (exportContractState):

   • Added this.logger.warn() in exportContractState when individual key fetches fail, replacing silent error swallowing while allowing the rest of the export to proceed.

3. Unit Test Coverage (src/modules/stellar/soroban/contract-state.service.spec.ts):

   • Verified that listStorageKeys() returns actual storage keys (admin_address, fee_rate) and never durability strings (persistent, temporary).
   • Verified that complex storage keys with embedded colons (user:account:12345) are preserved.
   • Verified fallback behavior for non-conforming cache keys.
   • Verified exportContractState() exports all cached state and logs a warning on key read failure.

Closes #87

[vercel]

@shobhamerabacha-star is attempting to deploy a commit to the Akargi Team on Vercel.

A member of the Team first needs to authorize it.

[ykargeee-bit]

✅ Ready to merge — all CI checks pass (Build and TypeScript Check ✅). The Vercel deployment failures are authorization issues unrelated to the code changes. This PR fixes an off-by-one bug in Soroban contract state key extraction and includes comprehensive tests. Safe to merge when a maintainer with write access reviews.