Drop Ethereum.chainConfig and consistently read chain configuration from blockchain.Config() to avoid dual sources of truth.
Changes include API/backend call sites and DebugAPI constructor cleanup. No functional behavior change is intended.
- Add error returns to Database.Reader() and NodeIterator() methods
- Introduce committed flag to prevent usage of tries after commit
- Update callers to handle new error signatures
- Add MustNodeIterator() helper for backward compatibility
Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
