Create a questionnaire template as the Retraced admin

Creates an empty draft template. The admin twin of POST /api/questionnaires/templates — same write, same service, but gated on admin:questionnaire:create, which only RETRACED_ADMIN holds. Every template created here is therefore Retraced-owned and starts inactive, so it stays out of the shared pool until it is switched on. Nothing is cloned and the name is not checked for uniqueness: one company may hold several templates under one name.