Verify iOS CoreNFC integration completeness

[gary-quinn]

Summary

Repository shows 99.4% Kotlin, 0.6% Swift. It's unclear how much of the CoreNFC integration is fully implemented vs stubbed.

Questions to Verify

1. Does NDEF read/write work end-to-end on iOS?
2. Does raw APDU transceive work for ISO 7816 and MiFare tags on iOS?
3. Are all NFCTagReaderSession delegate callbacks properly handled?
4. Is NFCNDEFReaderSession used for NDEF operations?
5. Are iOS-specific errors (e.g., NFCReaderError) mapped to the common error model?

Suggested Fix

• Add iOS-specific integration tests (XCTest or Kotlin/Native test task)
• If any features are stubbed, document them as "not yet implemented" in the README platform differences table