[Backend] sorobanService.simulateContractCall: extract STALE_THRESHOLD_MS / fee / placeholder source magic

[EbukaMoses]

Description

close #640
close #791
close #793

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🔧 Refactoring (no functional changes)
• ⚡ Performance improvement
• 🧪 Test addition or update

Related Issues

Closes #

Changes Made

Testing

Test Coverage

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed

Test Steps

Breaking Changes

Breaking Changes:

Migration Guide:

Screenshots/Demo

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published
• I have checked for breaking changes and documented them if applicable

Additional Notes

[ogazboiz]

hey, main now has stricter TypeScript (#735 just merged) which exposes a real type issue:

src/services/sorobanService.ts: error TS2352:
  Conversion of type 'Hash' to type 'Uint8Array' may be a mistake
  because neither type sufficiently overlaps with the other.

addr.contractId() returns Hash (a soroban-sdk type), not Uint8Array directly. The fix is to double-cast through unknown:

new Uint8Array(addr.contractId() as unknown as ArrayBufferLike)

or use Buffer.from(addr.contractId()) if Hash has a toJSON / [Symbol.iterator]. Same change needed in both src/services/sorobanService.ts and src/workers/soroban-event-worker.ts.

once that's fixed plus a rebase on main, CI should clear.

[ogazboiz]

two distinct build failures here:

1. src/services/sorobanService.ts:74 — Account (and TransactionBuilder, Networks) is now undeclared. you dropped the const { TransactionBuilder, Account, Networks } = await import(...) but the function still uses all three. either add a top-level static import:

   import { TransactionBuilder, Account, Networks } from '@stellar/stellar-sdk';

   or keep the dynamic import.

2. src/services/sorobanService.ts:57 and src/workers/soroban-event-worker.ts:55 — hash as Uint8Array is still flagged because Hash and Uint8Array don't overlap structurally in TS. the cast needs to bridge through unknown:

   return StrKey.encodeContract(Buffer.from(hash as unknown as Uint8Array));

   or if Hash exposes a .value() getter that returns the buffer, use that directly: Buffer.from(hash.value()).

once those build, this PR's scope (the constant extraction) is fine to land.

if you want to keep contributing, join us on Telegram: https://t.me/+DOylgFv1jyJlNzM0

[ogazboiz]

clean readability refactor, the magic literals (fees 100/1000, the 30s timeout, the simulation placeholder account) are pulled into named, documented constants with no behavior change, and the STALE_THRESHOLD_MS doc is a nice touch. ci is green. merging.