Add UserService (GetMe, UpdateMe, admin CRUD with block/unblock),
UserHandler (/users, /users/me), ACLHandler (GET/PUT /acl/:type/:id),
AuditHandler (GET /audit with all filters). Fix UserRepo.Update to
include is_blocked. Wire all remaining routes.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
