Auto-select newly created character in selection screen

After creating a character, automatically select it in the character
list instead of defaulting to the previously selected character.

Changes:
- Added selectCharacterByName() method to CharacterScreen
- Store created character name in Application
- On creation success, auto-select the new character by name
- Falls back to saved selection if new character name doesn't match

include/core/application.hpp

@@ -107,6 +107,7 @@ private:
 
     AppState state = AppState::AUTHENTICATION;
     bool running = false;
+    std::string pendingCreatedCharacterName_;  // Auto-select after character creation
     bool playerCharacterSpawned = false;
     bool npcsSpawned = false;
     bool spawnSnapToGround = true;