Function SendNotification 

pub async fn SendNotification(
    SideCarIdentifier: String,
    Method: String,
    Parameters: Value,
) -> Result<(), VineError>

Sends a notification to a sidecar without waiting for a response.

Note: This does not include a timeout parameter (unlike SendRequest). Notifications are sent as fire-and-forget messages.

use serde_json::json;
SendNotification(
    "cocoon-main".to_string(),
    "UpdateTheme".to_string(),
    json!({"theme": "dark"}),
).await?;