test(streams): add contract schema validation and flags u32 round-trip for parseStreamInfo (closes #595)

[martinss16kf]

Summary

Closes #595

Adds explicit schema tests against the on-chain Soroban contract's actual StreamInfo structure (contracts/stream/src/storage.rs) to prevent model drift in parseStreamInfo. Specifically tests that flags are decoded strictly from the flags: u32 bitmask and that standalone boolean fields are ignored.

Key Changes

• src/streams.ts:
  • Exported parseStreamInfo to enable direct unit testing and contract schema verification.
  • Hardened key extraction in parseStreamInfo to reliably handle both scvSymbol and scvString ScVal key types.
• src/tests/parse-stream-info.test.ts:
  • Added comprehensive test suite: parseStreamInfo — contract schema validation and flags: u32 round-trip (#595).
  • Added helper buildContractStreamInfoScVal reflecting exact Soroban contract storage layout.
  • Tests canonical StreamInfo ScVal map round-trip.
  • Tests model drift prevention (ensures standalone bool fields are ignored in favor of flags: u32).
  • Tests all permutations of flags: u32 bitmask flags (FLAG_PAUSED, FLAG_CANCELLED, FLAG_CLAWBACK_ENABLED) and higher bits.
  • Verifies 128-bit integer precision preservation for rate_per_second and withdrawn.
  • Verifies parity between symbol and string ScVal keys.
  • Verifies clean serialization via .toJSON().
  • Tests end-to-end contract round-trip via StreamsModule.get().

Verification

• npx vitest run src/tests/parse-stream-info.test.ts -> 13/13 passed (100%).
• npx vitest run -> 81/81 files passed (1028 passed, 0 failures).
• npx tsc --noEmit -> Clean (0 errors).