Function append_safeguard_fallback_notice 

pub fn append_safeguard_fallback_notice(
    response: String,
    notice: Option<&SafeguardFallbackNotice>,
) -> String

Render a safeguard fallback as display-only text at a runtime delivery boundary. The provider-owned notice is the canonical accepted-route fact; this helper only resolves its localized presentation when a caller needs a text surface (direct Agent, CLI, RPC, or ACP).