Issue: Remove `LegacyUser` function from `auth.types.ts`

[Villarley]

Issue: Remove LegacyUser function from auth.types.ts

Description

The file src/types/auth.types.ts still contains a LegacyUser function/type definition that is no longer used in the codebase.
This creates unnecessary confusion and technical debt in the authentication type system.

What is expected

• Completely remove the LegacyUser function/type from auth.types.ts.
• Ensure no other modules, services, or tests import or reference LegacyUser.
• Keep the file focused only on the types currently in use for authentication (JWT payload, session types, etc.).

What should be modified

1) Code Cleanup

• Delete the LegacyUser function/type from src/types/auth.types.ts.

2) References

• Run a project-wide search for LegacyUser.
• Remove any leftover imports or usage across modules.

3) Tests

• Ensure no tests are referencing LegacyUser.
• Run full test suite to confirm removal does not break other modules.

4) Documentation

• If mentioned in docs or comments, remove references to LegacyUser.

Acceptance criteria

• src/types/auth.types.ts contains no LegacyUser function/type.
• No other code references LegacyUser.
• All tests pass successfully.
• Documentation and comments remain aligned with the current type system.

Rollback plan

• If removal causes issues in unexpected areas, revert to the previous commit and re-evaluate where LegacyUser might still be required.
• As a fallback, comment the type instead of deleting to confirm unused status.

[raizo07]

Hello, I'll like to be assigned to work on this issue. I'm a Dev with over four years experience.

[Ulatex1905]

Hello, I am Santiago Ulate and I would like to be assigned to work on this issue.