fix: clean up combat text, cast bars, and aura cache on entity destroy

When SMSG_DESTROY_OBJECT removes an entity, now also purge combat text
entries targeting that GUID (prevents floating damage numbers on despawned
mobs), erase unit cast state (prevents stale cast bars), and clear cached
auras (prevents stale buff/debuff data for destroyed units).

src/game/game_handler.cpp

@@ -13018,8 +13018,21 @@ void GameHandler::handleDestroyObject(network::Packet& packet) {
     // Clean up quest giver status
     npcQuestStatus_.erase(data.guid);
 
+    // Remove combat text entries referencing the destroyed entity so floating
+    // damage numbers don't linger after the source/target despawns.
+    combatText.erase(
+        std::remove_if(combatText.begin(), combatText.end(),
+            [&data](const CombatTextEntry& e) {
+                return e.dstGuid == data.guid;
+            }),
+        combatText.end());
+
+    // Clean up unit cast state (cast bar) for the destroyed unit
+    unitCastStates_.erase(data.guid);
+    // Clean up cached auras
+    unitAurasCache_.erase(data.guid);
+
     tabCycleStale = true;
-    // Entity count logging disabled
 }
 
 void GameHandler::sendChatMessage(ChatType type, const std::string& message, const std::string& target) {