Feature request: Native account linking UI

Feature: Account linking means securely connecting multiple IdPs to a single user. Currently this is available in actions or other customization, but not natively. The current default behavior is that different IdPs (e.g. social providers like Google and Meta) create their own separate user accounts.

Description: Account linking is well-established as a core workflow in Auth0 and other IdPs, and Auth0 has devoted significant attention to it in the past.

However, all three of Auth0’s 1st-party solutions are broken and unmaintained: the extension, the client-side example, and the server-side example.

Use-case: Users may posses several of the available social login options, and all should function the same to the extent that that would be valid. For example perhaps they sign up using Google, and then later forget which it was and try to log in with Facebook. Currently they would get two separate accounts. Handling this case nicely is a basic requirement for good UX, but currently requires custom code.