Game.ts

import { Application, Container } from 'pixi.js';
import * as TWEEN from '@tweenjs/tween.js';
import { COLORS } from '../constants';
import { InputManager } from '../systems/InputManager';
import { AudioManager } from '../systems/AudioManager';
import { AssetManager } from '../systems/AssetManager';
import { PhysicsWorld } from '../systems/PhysicsWorld';
import { SceneManager } from './SceneManager';

/**
 * Top-level game orchestrator. Owns the PIXI application, systems (input,
 * audio, physics, assets), and the scene manager.
 *
 * Lifecycle:
 *   const game = new Game();
 *   await game.init(rootElement);   // bootstraps PIXI + Rapier
 *   await game.scenes.switch(MenuScene);
 *
 * The render loop is driven by PIXI's ticker; per-frame logic delegates to
 * SceneManager.update(dt). The canvas auto-resizes to the parent and propagates