Draft: [skip ci] Redesign the Orbit UI with Pajamas components

What does this MR do and why?

This is a draft working MR. It holds the whole Orbit UI redesign in one place, so the team can check it locally against the Claude Design canvas. After validation, we will split it into smaller MRs. Do not review line by line yet.

• Rebuilds the Orbit pages with Pajamas components to match the design: Your work > Orbit, group Settings > Orbit, Admin area > Orbit, and the Orbit default group in Preferences.
• Adds a trial flow on SaaS, behind the orbit_trial feature flag. Eligible groups start a free trial with orbitStartTrial. Beta and paid groups turn on directly. Self-managed and Dedicated show Contact sales.
• Turns Orbit in GitLab Duo on by default when Orbit is available. The per-user toggle is removed.
• Shows the top-level group's Orbit status to members who belong only to a subgroup. This uses the new orbitRootGroupStatuses field.
• Applies the decisions from the 2026-10-02 sync.

References

• Design canvas
• Sync transcript
• Related: trial end handling

Known follow-ups

• Browser check of every design lane is not complete. The key lanes were checked; the Admin page is checked by specs only, because SaaS simulation hides it.
• Admin page: confirm that admins who are not group Owners can select rows (the table now takes a selection rule).
• Old tracking events that lost their callers: mark them removed, or track them again.
• One shared GraphQL fragment for the Orbit group fields. Pagination beyond 10 groups on the Off page and for subgroup-only rows.
• Small cleanups: dead code from the removed per-user Orbit toggle, a smaller alert component on the group settings page, trial terms from the backend.

Screenshots or screen recordings

We will add screenshots for each design lane after the browser verification pass.

How to set up and validate locally

1. Simulate SaaS with GITLAB_SIMULATE_SAAS=1. In the Rails console, enable the knowledge_graph and orbit_trial feature flags, for example Feature.enable(:orbit_trial).
2. For trials, point the GDK at a local CustomersDot with CUSTOMER_PORTAL_URL.
3. Go to http://127.0.0.1:3000/dashboard/orbit as an Owner of a top-level group. Then go there as a member.
4. Go to the Settings > Orbit page of a top-level group.

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.