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/tui/app.rs

@@ -369,7 +369,7 @@ impl App {
             }
         };
 
-        match client.send_message(&peer, &encoded).await {
+        match client.send_message(&peer, Some(&self.our_fp), &encoded).await {
             Ok(_) => {
                 self.add_message(ChatLine {
                     sender: self.our_fp[..12].to_string(),