ui: resolve chat sender names at render time to fix [Say] prefix

When SMSG_MESSAGECHAT arrives before the entity has spawned or its
name is cached, senderName is empty and messages fell through to the
generic '[Say] message' branch. Fix:

- GameHandler::lookupName(guid): checks playerNameCache then entity
  manager (Unit subclass cast) at call time
- Chat display: resolves senderName via lookupName() at render time
  so messages show "Name says: msg" even if the name was unavailable
  when the packet was first parsed

include/game/game_handler.hpp

@@ -823,6 +823,22 @@ public:
 
     // Player GUID
     uint64_t getPlayerGuid() const { return playerGuid; }
+
+    // Look up a display name for any guid: checks playerNameCache then entity manager.
+    // Returns empty string if unknown. Used by chat display to resolve names at render time.
+    const std::string& lookupName(uint64_t guid) const {
+        static const std::string kEmpty;
+        auto it = playerNameCache.find(guid);
+        if (it != playerNameCache.end()) return it->second;
+        auto entity = entityManager.getEntity(guid);
+        if (entity) {
+            if (auto* unit = dynamic_cast<const Unit*>(entity.get())) {
+                if (!unit->getName().empty()) return unit->getName();
+            }
+        }
+        return kEmpty;
+    }
+
     uint8_t getPlayerClass() const {
         const Character* ch = getActiveCharacter();
         return ch ? static_cast<uint8_t>(ch->characterClass) : 0;

src/ui/game_screen.cpp

@@ -1181,6 +1181,16 @@ void GameScreen::renderChatWindow(game::GameHandler& gameHandler) {
         if (!shouldShowMessage(msg, activeChatTab_)) continue;
         std::string processedMessage = replaceGenderPlaceholders(msg.message, gameHandler);
 
+        // Resolve sender name at render time in case it wasn't available at parse time.
+        // This handles the race where SMSG_MESSAGECHAT arrives before the entity spawns.
+        const std::string& resolvedSenderName = [&]() -> const std::string& {
+            if (!msg.senderName.empty()) return msg.senderName;
+            if (msg.senderGuid == 0) return msg.senderName;
+            const std::string& cached = gameHandler.lookupName(msg.senderGuid);
+            if (!cached.empty()) return cached;
+            return msg.senderName;
+        }();
+
         ImVec4 color = getChatTypeColor(msg.type);
 
         // Optional timestamp prefix
@@ -1208,36 +1218,36 @@ void GameScreen::renderChatWindow(game::GameHandler& gameHandler) {
             renderTextWithLinks(tsPrefix + processedMessage, color);
         } else if (msg.type == game::ChatType::TEXT_EMOTE) {
             renderTextWithLinks(tsPrefix + processedMessage, color);
-        } else if (!msg.senderName.empty()) {
+        } else if (!resolvedSenderName.empty()) {
             if (msg.type == game::ChatType::SAY ||
                 msg.type == game::ChatType::MONSTER_SAY || msg.type == game::ChatType::MONSTER_PARTY) {
-                std::string fullMsg = tsPrefix + tagPrefix + msg.senderName + " says: " + processedMessage;
+                std::string fullMsg = tsPrefix + tagPrefix + resolvedSenderName + " says: " + processedMessage;
                 renderTextWithLinks(fullMsg, color);
             } else if (msg.type == game::ChatType::YELL || msg.type == game::ChatType::MONSTER_YELL) {
-                std::string fullMsg = tsPrefix + tagPrefix + msg.senderName + " yells: " + processedMessage;
+                std::string fullMsg = tsPrefix + tagPrefix + resolvedSenderName + " yells: " + processedMessage;
                 renderTextWithLinks(fullMsg, color);
             } else if (msg.type == game::ChatType::WHISPER ||
                        msg.type == game::ChatType::MONSTER_WHISPER || msg.type == game::ChatType::RAID_BOSS_WHISPER) {
-                std::string fullMsg = tsPrefix + tagPrefix + msg.senderName + " whispers: " + processedMessage;
+                std::string fullMsg = tsPrefix + tagPrefix + resolvedSenderName + " whispers: " + processedMessage;
                 renderTextWithLinks(fullMsg, color);
             } else if (msg.type == game::ChatType::WHISPER_INFORM) {
                 // Outgoing whisper — show "To Name: message" (WoW-style)
-                const std::string& target = !msg.receiverName.empty() ? msg.receiverName : msg.senderName;
+                const std::string& target = !msg.receiverName.empty() ? msg.receiverName : resolvedSenderName;
                 std::string fullMsg = tsPrefix + "To " + target + ": " + processedMessage;
                 renderTextWithLinks(fullMsg, color);
             } else if (msg.type == game::ChatType::EMOTE ||
                        msg.type == game::ChatType::MONSTER_EMOTE || msg.type == game::ChatType::RAID_BOSS_EMOTE) {
-                std::string fullMsg = tsPrefix + tagPrefix + msg.senderName + " " + processedMessage;
+                std::string fullMsg = tsPrefix + tagPrefix + resolvedSenderName + " " + processedMessage;
                 renderTextWithLinks(fullMsg, color);
             } else if (msg.type == game::ChatType::CHANNEL && !msg.channelName.empty()) {
                 int chIdx = gameHandler.getChannelIndex(msg.channelName);
                 std::string chDisplay = chIdx > 0
                     ? "[" + std::to_string(chIdx) + ". " + msg.channelName + "]"
                     : "[" + msg.channelName + "]";
-                std::string fullMsg = tsPrefix + chDisplay + " [" + tagPrefix + msg.senderName + "]: " + processedMessage;
+                std::string fullMsg = tsPrefix + chDisplay + " [" + tagPrefix + resolvedSenderName + "]: " + processedMessage;
                 renderTextWithLinks(fullMsg, color);
             } else {
-                std::string fullMsg = tsPrefix + "[" + std::string(getChatTypeName(msg.type)) + "] " + tagPrefix + msg.senderName + ": " + processedMessage;
+                std::string fullMsg = tsPrefix + "[" + std::string(getChatTypeName(msg.type)) + "] " + tagPrefix + resolvedSenderName + ": " + processedMessage;
                 renderTextWithLinks(fullMsg, color);
             }
         } else {