FEAT | Add config support to login flow

[shevchanski]

Description

Add support for the Facebook Login for Business (BISU) flow via a new configId prop on the <Login> component and a configId option in useLogin / login().

When configId is provided, the login call sets config_id, response_type: 'code', and override_default_response_type: true on the underlying FB.login() call and returns a code instead of an accessToken. TypeScript discriminated unions enforce that configId and scope are mutually exclusive at compile time.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Testing

• Added/updated tests
• All tests pass
  • All unit tests
  • e2e tests
• Tested with real Facebook integration

Note:

• Struggled to get the e2e (Playwright) suite running locally, so currently left as is. Going to check it later.
• Also, there is a mismatch between actual test configuration and one described in the CONTRIBUTING.md (Cypress/Playwright)

Documentation

• Updated README
• Updated API docs
• Added examples

Checklist

• Self-review completed
• TypeScript types updated
• No breaking changes (or properly documented)

[shevchanski]

Examples of tests with real FB integration