Refactor PlayerListener and add delayed server state updates for web integration.

api/src/main/java/com/alttd/chat/web/handler_class/PlayerListState.java

@@ -0,0 +1,15 @@
+package com.alttd.chat.web.handler_class;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.util.List;
+import java.util.UUID;
+
+@Data
+@NoArgsConstructor
+public class PlayerListState {
+
+    private List<UUID> activePlayers;
+
+}