📘 Update "Activate-Account" service documentation to reflect current architecture

As a DevOps documentation maintainer, 
I want to update the "Activate Account" service documentation in the Guidebook 
to include all currently deployed Cloud Run services 
and relevant repositories, 
so that internal stakeholders and developers have accurate, 
up-to-date technical and architectural information.

📚 Background

The current documentation for the Activate Account service at:

• Guidebook page
• GitLab markdown source

...is outdated and does not reflect the full architecture. It only lists the primary frontend and backend components, omitting the following active Cloud Run instances:

• acc-selector-data
• acc-selector-initial
• account-data-manager
• api
• bad-data-notifier
• entra-event-handler
• frontend
• internal-api
• remote-log-server
• user-updater-jackdaw

And the service now spans multiple repositories beyond just the frontend and backend, including infrastructure, data pipelines, and API separation.

To maintain accuracy and compliance with internal service documentation standards, the Guidebook must be updated accordingly.

✅ Acceptance Criteria

• List of all active Cloud Run services added to the Architecture section.
• Description of each Cloud Run service added or updated with brief purpose/function (+envs).
• Additional GitLab repositories related to Activate Account listed and linked.