[ psic4t/nospeak ] fix: NIP-17 Kind 15 file encryption interoperability with Amethyst
- Add hex encoding support for decryption-key/nonce (auto-detect hex vs base64url)
- Change nonce size from 12 to 16 bytes for Amethyst compatibility
- Output key/nonce as hex instead of base64url when sending
- Upload encrypted blobs as application/octet-stream for .bin URLs
- Add key size validation (AES-128/256 only)
- Add comprehensive tests for FileEncryption module
- Update messaging spec with new interoperability scenarios

GitHub
fix: NIP-17 Kind 15 file encryption interoperability with Amethyst · psic4t/nospeak@031a6ea
- Add hex encoding support for decryption-key/nonce (auto-detect hex vs base64url)
- Change nonce size from 12 to 16 bytes for Amethyst compatibili...