function requiredEnv(name: string): string {
  const value = process.env[name];
  if (!value) {
    throw new Error(`${name} is required`);
  }
  return value;
}

// Environment-only knobs. Per-storyboard tuning (aspect, fps, bitrate,
// voice, prompts, brand…) lives on the Storyboard object itself. See
// src/storyboard.ts.

export const APP_URL = requiredEnv('APP_URL');
export const DASHBOARD_PATH = '/dashboard';

// Per-target storage state. render.sh sets AUTH_STATE_FILE to auth.local.json
// or auth.prod.json so a stale local token can't be reused against prod.
export const AUTH_STATE_PATH = process.env.AUTH_STATE_FILE ?? 'auth.json';
export const OUTPUT_DIR = 'output';

// Frames of head-room kept in front of sceneStart when trimming. Shared by
// the video trim and the narration manifest so cue offsets line up with the
// trimmed timeline. Not tuned per storyboard: same lead-in for any cut.
export const LEAD_IN_S = 0.12;