FULLSTACK - Use real data on search page

[hansjhaland]

What

• Update backend GET /user/{id} and GET /users endpoints:

  • Join User with UserCohort and Cohort tables.
  • Ensure each user returned includes their associated cohort information.

• Update frontend search page:

  • Adjust DTO and API calls to handle the new user + cohort response format.
  • Display cohort details alongside users in the UI.

---

Why

• The search page should display real data instead of placeholders.
• Users need to be shown together with their cohort for meaningful search results.
• Keeps frontend and backend aligned with the new data model.

---

Acceptance Criteria

• Backend GET /user/{id} returns a user object that includes cohort information.

• Backend GET /users returns a list of users, each with cohort information.

• Frontend consumes the updated response structure without errors.

• Search page displays users with their cohort.

• Profile in header displays users with their cohort.

• Unit/integration tests updated to cover new structure.