IdpHandler

Interface for handling authentication with external Identity Providers (IdPs).

This interface defines the contract for implementations that manage authentication flows with third-party identity providers such as Google, Facebook, Apple, etc. Each implementation is responsible for:

1. Launching the appropriate authentication UI or flow

2. Handling the authentication response

3. Extracting tokens and other relevant information

4. Returning a standardized result

Implementations should handle all provider-specific details internally, including error handling, token validation, and user cancellation.