Alias TTL renews only on authenticated actions (sending messages)

- Sending a message includes `from` fingerprint
- Server renews alias TTL on send (proves identity: you encrypted it)
- Polling/receiving does NOT renew (anyone can spam messages to you)
- Key registration does NOT renew (separate concern)

This prevents alias keepalive attacks where someone spams a user
just to keep their alias from expiring.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/crates/warzone-client/src/cli/send.rs

@@ -82,7 +82,7 @@ pub async fn run(recipient_fp: &str, message: &str, server_url: &str) -> Result<
     let encoded = bincode::serialize(&wire_msg)
         .context("failed to serialize wire message")?;
 
-    client.send_message(recipient_fp, &encoded).await?;
+    client.send_message(recipient_fp, Some(&our_pub.fingerprint.to_string()), &encoded).await?;
 
     println!("Message sent to {}", recipient_fp);
     Ok(())