Made of little things.

import { config } from '@napplet/sdk';
import { runtimeHasDomain } from './domain-availability.js';
import { DEFAULT_MOVE_SPEED } from './simulation.js';
import settingsSchema from '../config.schema.json';
export type Settings = { sound: boolean; reducedMotion: boolean; movementSpeed: number };
export function subscribeSettings(apply: (settings: Settings) => void): () => void {
  let close: (() => void) | undefined;
  let stopped = false;
  if (runtimeHasDomain('config')) {
    void (async () => {
      if (!config.schema) await config.registerSchema(settingsSchema as Parameters<typeof config.registerSchema>[0]);
      if (stopped) return;
      const subscription = config.subscribe(values => apply({
        sound: values.sound !== false,
        reducedMotion: values.reducedMotion === true || matchMedia('(prefers-reduced-motion: reduce)').matches,
        movementSpeed: typeof values.movementSpeed === 'number' ? Math.max(1, Math.min(10, values.movementSpeed)) : DEFAULT_MOVE_SPEED,
      }));
      close = () => subscription.close();
    })().catch(() => { /* An optional host enhancement; keep local defaults. */ });
  }
  return () => { stopped = true; close?.(); };
}