Allow Credential
A credential descriptor pairing a credential ID with optional transport hints.
Used in WebAuthnProvider.authenticate to constrain which passkeys the authenticator offers and to indicate how the client can reach the authenticator (e.g., "internal", "hybrid", "usb", "ble", "nfc"). Including transport hints enables cross-device authentication flows such as QR code scanning.
When transports is null, the authenticator uses its default transport selection. Unknown transport strings are passed through without validation — the browser or OS ignores values it does not recognize.