Port the admin action endpoints to the Huma-backed /api/v2:
- GET /admin/overview instance counts + license snapshot
- POST /admin/users create a user (201)
- PATCH /admin/users/{id}/admin promote/demote (*bool, nil = unchanged)
- PATCH /admin/users/{id}/status set status (*Status, nil = unchanged)
- DELETE /admin/users/{id} delete (mode=now|scheduled, 204)
- PATCH /admin/projects/{id}/owner reassign project owner
All sit behind the existing gateV2AdminRoutes path middleware (admin + license
gate, 404 on failure), so no per-handler permission checks are added. The
hand-registered PATCH routes carry genuine partial semantics, which AutoPatch
does not synthesise. The admin user response reuses the existing
pkg/routes/api/shared package.
Move the admin overview computation and struct into models.BuildOverview /
models.Overview, the admin create-user flow into models.CreateUserAsAdmin /
models.CreateUserBody, and the admin user response view into a new
pkg/routes/api/shared package (shared.AdminUser / shared.NewAdminUser) so both
the v1 and v2 admin routes call the same code. The v1 handlers are refactored
onto these helpers and stay byte-identical on the wire.
kolaente