BUG: guest users making WB contributions are counted as Alkemio team users

[anneklok]

Describe the bug
Guest users who make a whiteboard contribution are being counted as Alkemio team users in analytics.

As a result:

• The number of “active Alkemio users” is inflated compared to the actual number of Alkemio accounts.
• The number of “active non-Alkemio users” is lower than the actual number.

This creates an inconsistency between analytics data and the real number of existing user accounts.

The issue appears to be limited to whiteboard contribution events.

To Reproduce
Steps to reproduce the behavior:

1. Go to the Sprint Review dashboard in Kibana.
2. Scroll to the section “Alkemio usage this sprint”.
3. Check the visualization showing active users.
4. Observe the number of active users on a given day (e.g., 31 users on 25/02).
5. Compare this with the actual number of existing Alkemio accounts (~18–20).
6. Inspect the underlying events in Elastic.
7. Notice that multiple whiteboard contribution events are linked to user IDs that do not correspond to existing user accounts (unfindable users).

Expected behavior

• Guest users should be clearly identified in tracking (e.g., guest=true or a dedicated user type).
• Whiteboard contribution events from guest users should not be counted as Alkemio team users.
• Active user metrics should accurately reflect:
  • Active Alkemio team users
  • Active non-Alkemio users
• Analytics should align with the actual number of existing user accounts.

Additional context
Add any other context about the problem here.

Areas that will be affected as part of the fix
Optional, to be added by developer if relevant