Function create_subscription_for_self 

pub fn create_subscription_for_self(
    bridge: &mut SignalBridge,
    subscription_id: &str,
    since_timestamp: u64,
) -> Result<String, Box<dyn Error>>

Creates a Nostr subscription filter for messages to this node

Arguments

• bridge - Signal bridge instance
• subscription_id - Subscription identifier
• since_timestamp - Optional timestamp to filter messages since

Returns

REQ message JSON