Function emit_before_tool_call 

pub async fn emit_before_tool_call(
    hook_bus: &Arc<HookBus>,
    tool_name: &str,
    runtime_tool_name: Option<&str>,
    input: Value,
    session_id: Option<&str>,
) -> HookResult

Emit a before_tool_call event and include the runtime tool name when it differs from the API-safe name. session_id is the owning conversation (None for workers → JSON null, unchanged).