Function set_deprecated 

pub async fn set_deprecated(
    store: &TemplateStore,
    id: &str,
    reason: Option<String>,
    by: Option<&str>,
    deprecated: bool,
) -> CliResult<TemplateStatus>

Available on crate feature templates only.

Retire (Some) or revive (None) a template.

Deprecation is template-wide, not per version: a build that should not be used simply never gets launched (or gets deleted). A deprecated template keeps serving callers who pin or ride stable — retiring must not hard-break them — but every trigger warns and listings mark it. Returns the resulting status.