Fix crash in character creation by deferring callback to next update

The charCreateCallback was firing synchronously during ImGui render,
causing a state transition before the create screen's ImGui::End() was
called. Defer the callback to GameHandler::update() and ensure update()
runs during CHARACTER_CREATION and CHARACTER_SELECTION states.

include/game/game_handler.hpp

@@ -525,6 +525,9 @@ private:
     WorldConnectSuccessCallback onSuccess;
     WorldConnectFailureCallback onFailure;
     CharCreateCallback charCreateCallback_;
+    bool pendingCharCreateResult_ = false;
+    bool pendingCharCreateSuccess_ = false;
+    std::string pendingCharCreateMsg_;
 
     // ---- XP tracking ----
     uint32_t playerXp_ = 0;

src/core/application.cpp

@@ -344,11 +344,15 @@ void Application::update(float deltaTime) {
             break;
 
         case AppState::CHARACTER_CREATION:
-            // Character creation update
+            if (gameHandler) {
+                gameHandler->update(deltaTime);
+            }
             break;
 
         case AppState::CHARACTER_SELECTION:
-            // Character selection update
+            if (gameHandler) {
+                gameHandler->update(deltaTime);
+            }
             break;
 
         case AppState::IN_GAME:

src/game/game_handler.cpp

@@ -406,6 +406,14 @@ bool GameHandler::isConnected() const {
 }
 
 void GameHandler::update(float deltaTime) {
+    // Fire deferred char-create callback (outside ImGui render)
+    if (pendingCharCreateResult_) {
+        pendingCharCreateResult_ = false;
+        if (charCreateCallback_) {
+            charCreateCallback_(pendingCharCreateSuccess_, pendingCharCreateMsg_);
+        }
+    }
+
     if (!socket && !singlePlayerMode_) {
         return;
     }
@@ -852,9 +860,10 @@ void GameHandler::createCharacter(const CharCreateData& data) {
         characters.push_back(ch);
 
         LOG_INFO("Single-player character created: ", ch.name);
-        if (charCreateCallback_) {
+        // Defer callback to next update() so ImGui frame completes first
-            charCreateCallback_(true, "Character created!");
+        pendingCharCreateResult_ = true;
-        }
+        pendingCharCreateSuccess_ = true;
+        pendingCharCreateMsg_ = "Character created!";
         return;
     }