Function api_run_task_diffs 

pub fn api_run_task_diffs(
    corpus: &str,
    service: &str,
    previous: Option<&str>,
    current: Option<&str>,
    previous_status: Option<&str>,
    current_status: Option<&str>,
    offset: Option<usize>,
    page_size: Option<usize>,
    pool: &State<DbPool>,
) -> Result<Json<Vec<TaskDiffDto>>, Status>

Lists the individual tasks whose status changed between two snapshots of a (corpus, service) — the drill-down behind the comparison matrix (which documents regressed/improved). Optionally filtered to a previous_status/current_status transition and paginated (offset/page_size, default 100). 400 on a malformed date or status, 404 if the corpus/service is unknown.