Start an AI auto-categorisation run over the selected items and return a job to poll.

Admin-only: AI categorisation is an internal review tool, so regular users (customers) are blocked at the API (get_admin_user → 403), not just in the UI. get_admin_user checks the real session user, so an admin impersonating a customer can still run it.

Classified rows get a category (and, when include_eligibility, an R&D eligibility) and are flagged auto_categorised — the AI path never sets manual_override and never assigns a project/activity. Synthetic salary ids and ids not resolving to a live item on this claim are dropped (the claim-scoped query is the authorization boundary), so total reflects only real, processable rows.