Enable the Credential Executor to identify and pass on the login ID type used during authentication

[SajidMannikeri17]

Summary

Multiple login ID types (e.g. Mobile Number, Email, national ID) are already supported at login, but there is currently no way to identify which login ID type a user used for a given login attempt. This is needed because each ID type has its own validation rules, and the correct validation can only be applied once the type used is known.

Background / Problem

• Users can already log in using different login ID types.
• For a given login attempt, the system cannot currently tell which login ID type the user used.
• Since each login ID type has distinct validation rules, without knowing the type used, the correct validation cannot be applied to the submitted ID.

Use Cases

1. Type-aware validation. When a user submits a login ID, the ID is validated according to the login ID type they used (e.g. Mobile Number validation vs. Email validation).
2. No disruption to existing logins. Users on flows that use a single, fixed login ID type continue to log in exactly as before.

Acceptance Criteria

• The login ID type a user used for a given login attempt can be identified.
• The correct validation is applied based on the identified login ID type (e.g. Mobile Number validation vs. Email validation).
• Existing single login-ID-type flows continue to work without regression.
• The behaviour is documented for other teams/consumers.