feat: add TeamSpeak address resolver

crates/chanora_protocol/src/dto.rs

@@ -56,6 +56,13 @@ pub struct ChatMessage {
     pub target: MessageTarget,
 }
 
+/// A server-activity notification derived from TeamSpeak bookkeeping events.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ServerActivity {
+    /// Human-readable activity line.
+    pub message: String,
+}
+
 /// One connected client on the server.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ClientInfo {