build a space shooter game with vanilla JavaScript and canvas. no libraries. no frameworks. multi-file project structure.
PROJECT STRUCTURE: space-shooter/ index.html -- entry point, canvas setup, script imports in dependency order (config > audio > particles > background > enemies > player > ui > game) README.md -- what it is, how to run, controls, screenshot placeholder css/styles.css -- fullscreen canvas, cursor hidden during gameplay, no-select, overflow hidden js/ config.js -- color palette, speeds, enemy stats, sizes, all tuning constants game.js -- main game loop, state machine (menu/playing/paused/gameover), collision detection, damage numbers, screen shake