Initial release.

Added #

• NFC discovery and connection stream (onYubikeyConnected) exposing YubikeyDeviceInfo (device name, connection type, serial, firmware).
• isNfcSupported() / isNfcEnabled() runtime checks.
• OTP: readOtp({timeout}) reads Yubico OTP via NDEF over NFC.
• Challenge-Response: challengeResponse({challenge, slot}) performs HMAC-SHA1 on the YubiKey (slot 1 or 2).
• OATH: listOathCredentials(), calculateOathCode(id), calculateAllOathCodes() for TOTP/HOTP.
• FIDO2 / WebAuthn: fido2Register(...), fido2Authenticate(...), fido2Reset() via CTAP2.
• Typed exception hierarchy: YubikeyException, YubikeyNfcDisabledException, YubikeyNfcNotSupportedException, YubikeyTimeoutException, YubikeyCancelledException, YubikeyInvalidPinException (with retriesRemaining), YubikeyPinLockedException, YubikeyNoCredentialsException.
• Android implementation built on the official yubikit-android SDK 2.7.0.
• Example app with OTP, OATH, and FIDO2 tabs.
• 26 unit tests.

Platforms #

• Android (minSdk 23, targetSdk 34).
• iOS on the roadmap.