2.0.0 — Swift 6.1, Combine, URLSession, K1

First release in 4 years. A major migration under the hood; the public API is reshaped accordingly.

Highlights

• Swift 6.1 toolchain (Swift 5 language mode). Raises deployment targets to macOS 13 / iOS 16.
• RxSwift → Combine. ZilliqaServiceReactive now vends AnyPublisher<_, Zesame.Error> via service.combine.*. Rx APIs are removed.
• Async/await is the primary ZilliqaService API; Combine is a thin wrapper over it.
• K1 (libsecp256k1) replaces EllipticCurveKit for signing and key handling.
• URLSession replaces the previous HTTP stack. DefaultAPIClient now surfaces non-2xx HTTP responses as HTTPError.unacceptableStatusCode instead of masking them as decoding errors.
• CryptoSwift removed. Scrypt/PBKDF2/AES use CryptoKit and Apple's CommonCrypto.
• Protobuf regenerated against current apple/swift-protobuf.

Safety fixes

• Data(hex:) now rejects non-hex characters (previously silently truncated). Odd-length input is left-padded with a leading 0. A failable Data(validatingHex:) is available for untrusted input.
• KeyRestoration(privateKeyHexString:...) uses the failable variant and throws .badPrivateKeyHex on bad input.
• Combine publishers returned by callAsync cancel their underlying Task when the subscription is cancelled.

Tooling

• Pre-commit hooks: typos, SwiftFormat, SwiftLint, and a swift test gate.
• GitHub Actions CI runs the test suite on macOS with Xcode 16.
• Coverage tooling under scripts/ with a just cov / just cov-detailed entry point.
• 329 tests across 70 suites.

Dependencies

• K1 0.3.7+
• BigInt 5.7.0+
• swift-protobuf 1.26.0+

Change min/default gasLimit to 50

Merge pull request #52 from OpenZesame/increase_default_gasLimit

Increase min gasLimit to 50 for payments