chore: #fe drop unused assets

frontend/public/assets/background_layers/ground.png

frontend/public/assets/music/breakdown.wav

frontend/public/assets/music/win.wav

frontend/public/assets/sprites/player/hit-sheet.png

frontend/public/assets/sprites/player/misssing-sheet.png

frontend/public/assets/sprites/player/player.json

frontend/public/assets/sprites/player/player.png

frontend/src/js/game_over_scene.ts

frontend/src/js/welcome_scene.ts