feat: fire PLAYER_TARGET_CHANGED and PLAYER_LEVEL_UP addon events

Add a generic AddonEventCallback to GameHandler for firing named events
with string arguments directly from game logic. Wire it to the addon
system in Application.

New events fired:
- PLAYER_TARGET_CHANGED — when target is set or cleared
- PLAYER_LEVEL_UP(newLevel) — on level up

The generic callback pattern makes it easy to add more events from
game_handler.cpp without touching Application/AddonManager code.
Total addon events: 16 (2 world + 12 chat + 2 gameplay).

include/game/game_handler.hpp

@@ -283,6 +283,10 @@ public:
     using AddonChatCallback = std::function<void(const MessageChatData&)>;
     void setAddonChatCallback(AddonChatCallback cb) { addonChatCallback_ = std::move(cb); }
 
+    // Generic addon event callback: fires named events with string args
+    using AddonEventCallback = std::function<void(const std::string&, const std::vector<std::string>&)>;
+    void setAddonEventCallback(AddonEventCallback cb) { addonEventCallback_ = std::move(cb); }
+
     // Emote animation callback: (entityGuid, animationId)
     using EmoteAnimCallback = std::function<void(uint64_t, uint32_t)>;
     void setEmoteAnimCallback(EmoteAnimCallback cb) { emoteAnimCallback_ = std::move(cb); }
@@ -2639,6 +2643,7 @@ private:
     std::vector<std::string> joinedChannels_;   // Active channel memberships
     ChatBubbleCallback chatBubbleCallback_;
     AddonChatCallback addonChatCallback_;
+    AddonEventCallback addonEventCallback_;
     EmoteAnimCallback emoteAnimCallback_;
 
     // Targeting

src/core/application.cpp

@@ -360,6 +360,12 @@ bool Application::initialize() {
                     addonManager_->fireEvent(eventName, {msg.message, msg.senderName});
                 }
             });
+            // Wire generic game events to addon dispatch
+            gameHandler->setAddonEventCallback([this](const std::string& event, const std::vector<std::string>& args) {
+                if (addonManager_ && addonsLoaded_) {
+                    addonManager_->fireEvent(event, args);
+                }
+            });
             LOG_INFO("Addon system initialized, found ", addonManager_->getAddons().size(), " addon(s)");
         } else {
             LOG_WARNING("Failed to initialize addon system");

src/game/game_handler.cpp

@@ -4557,6 +4557,7 @@ void GameHandler::handlePacket(network::Packet& packet) {
                                 sfx->playLevelUp();
                         }
                         if (levelUpCallback_) levelUpCallback_(newLevel);
+                        if (addonEventCallback_) addonEventCallback_("PLAYER_LEVEL_UP", {std::to_string(newLevel)});
                     }
                 }
             }
@@ -13332,11 +13333,13 @@ void GameHandler::setTarget(uint64_t guid) {
     if (guid != 0) {
         LOG_INFO("Target set: 0x", std::hex, guid, std::dec);
     }
+    if (addonEventCallback_) addonEventCallback_("PLAYER_TARGET_CHANGED", {});
 }
 
 void GameHandler::clearTarget() {
     if (targetGuid != 0) {
         LOG_INFO("Target cleared");
+        if (addonEventCallback_) addonEventCallback_("PLAYER_TARGET_CHANGED", {});
     }
     targetGuid = 0;
     tabCycleIndex = -1;