server : use std::move whenever possible (#12936) * server : use std::move whenever possible * use r-value ref * Apply suggestions from code review Co-authored-by: Georgi Gerganov <ggerganov@gmail.com> * make task creation scoped * restore std::move * fix task_id not set correctly * apply changes from suggestion Co-authored-by: ggerganov <ggerganov@gmail.com> --------- Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>