Move agent todos above the session activity log

What does this MR do and why?

• Extracted the "Agent todos" section (heading, progress count, and checklist) into a new AgentTodos component
• AgentFlowDetails now renders the new AgentTodos component above the activity log
  • AgentFlowInfo is now just session information again, and the todos (when available) are no longer hidden behind the info toggle

References

• Related to Sessions details panel redesign: Move Agent Todos (#609574 - closed) • Allison Villa • 19.4 • On track
• Designs:
  • Full page view
  • Panel view

Screenshots or screen recordings

Side panel

Full page view

Recording of both

How to set up and validate locally

1. Prerequisite: Have GitLab Duo set up in your GDK
   • Have a Duo-enabled group and project in your GDK created by the Duo setup above
2. Prerequisite: Have GitLab Runner working
3. Start a GitLab Duo agent flow session that produces a plan (the agent emits todo_write tool calls). For example, open an issue and in Duo chat, ask it to implement the issue in a new MR
4. Once the session starts, open the session detail page and confirm the "Agent todos" section appears above the activity log
5. Open the same session in the AI side panel and confirm the "Agent todos" section appears above the activity log whether or not the "info" button is toggled

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.