(#18): merge combine-hud-game into main, fix conflicts

backend/src/index.ts

backend/types/User.ts

frontend/android/AndroidManifest.xml

frontend/assets/menu-textures.atlas

frontend/assets/menu-textures.png

frontend/core/src/com/game/tankwars/ReceiverHandler.java

frontend/core/src/com/game/tankwars/TankWarsGame.java

...core/src/com/game/tankwars/controller/GameController.java

...c/com/game/tankwars/controller/LeaderboardController.java

...ore/src/com/game/tankwars/controller/LoginController.java

.../src/com/game/tankwars/controller/MainMenuController.java

frontend/core/src/com/game/tankwars/model/CurrentUser.java

frontend/core/src/com/game/tankwars/model/Tank.java

frontend/core/src/com/game/tankwars/model/User.java

frontend/core/src/com/game/tankwars/view/GameScreen.java

frontend/core/src/com/game/tankwars/view/LoginScreen.java

frontend/core/src/com/game/tankwars/view/MainMenuScreen.java