InputManager.ts

/**
 * Unified input. Reads keyboard (arrows + WASD) and exposes a normalized
 * direction vector each frame. Also tracks pointer state and supports
 * subscribing to discrete key events (jump, pause, etc.).
 *
 * Touch support: a virtual joystick is not included by default — most polished
 * 2D games render a custom on-screen control. Hook touchstart/touchmove on
 * scenes that need it, or extend this class.
 */
type KeyHandler = () => void;

export class InputManager {
  /**
   * Movement keys the game always consumes. Combined with any key that has an
   * active onPress handler, these get preventDefault()'d on keydown so the
   * browser doesn't scroll the page (Arrow keys + Space) while playing.
   */
  private static readonly MOVE_KEYS = new Set([
    'ArrowUp',
    'ArrowDown',