Reconcile GitLab routes snapshot from master before blocking the sync gate

What does this MR do and why?

Refreshes test/routes/gitlab_routes.json from a pinned GitLab master SHA (991aae5d460f81fdbd7e114b788940b67161ddb4) so router main becomes byte-identical to GitLab master.

This is the reconcile prerequisite for step 6 of the routing-drift work item: making cells-routes:router-in-sync blocking. The gate byte-diffs router main against a GitLab MR's snapshot, so router main must have zero drift against master before allow_failure: true is removed in GitLab. Flipping while the snapshots differ would hard-block every route-touching GitLab MR immediately.

The change is a snapshot refresh only - both affected routes are already matched by the existing /api/* router pattern (claim: null), so no routing rule or guard change is needed:

• remove /api/:version/ai/duo_workflows/flow_callbacks and /api/:version/ai/duo_workflows/flow_callbacks/:id
• add /api/:version/ai/duo_workflows/workflows/:workflow_id/restart

References

• Work item: gitlab-com/gl-infra/tenant-scale/cells-infrastructure/team#723 (closed)
• Paired GitLab flip MR (removes allow_failure): (link once created)
• Snapshot source: config/routing/gitlab_routes.json@991aae5d460f81fdbd7e114b788940b67161ddb4

How to set up and validate locally

1. npm run download-gitlab-routes -- 991aae5d460f81fdbd7e114b788940b67161ddb4
2. npm run generate-route-guards
3. npm run test -- routes.spec.ts (snapshot test passes without -u)
4. Verify zero drift against GitLab master: curl -s "https://gitlab.com/gitlab-org/gitlab/-/raw/master/config/routing/gitlab_routes.json" | diff - test/routes/gitlab_routes.json -> no output.

MR acceptance checklist

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