videobook 0.2.4

Added

• Image and video model pickers show frontier rankings from the offline
  @apicity/cost snapshot, with rank, Elo and price for the selected operation.
  Other models follow in their existing order; unconfigured providers are
  marked unavailable. Saved selections and default models stay unchanged.

• MachGen as a video provider, with six models: MiniMax H3, Seedance
  2.5, Seedance 2.0, Wan 3.0 and HappyHorse 1.1 for text, frame and
  reference video, and Grok Imagine Video 1.5 for image-to-video. Each
  model offers its own resolutions, durations and aspect ratios, and
  cost estimates come from the @apicity/cost MachGen per-second rates.
  Wan 3.0 always sends MachGen's documented adaptive, 30 fps, with-audio
  config. Generations run as provider tasks: Videobook polls MachGen and
  downloads the finished video with the API key.

• MACHGEN_API_KEY is a managed key. videobook config, 1Password
  resolution and the provider keys panel include it. Without it, MachGen
  generations stop with "MACHGEN_API_KEY environment variable is not set"
  before an asset is created, and pending MachGen tasks wait unpolled.

• Seedance 2.5 Draft Complete (kie:bytedance/seedance-2-5-draft)
  renders the 1080p final of a 480p Seedance 2.5 draft from the draft's
  Kie task id. A draft rendered in the same book supplies the billed
  seconds and reference video seconds for the estimate. The Kie Seedance
  2.5 model gains the matching draft option.

Changed

• Upgrade all application @apicity/* dependencies to 0.17.0 and add
  @apicity/machgen.
• Kie Seedance 2.5 estimates use the 2026-10-22 rates, for example
  $0.79 per second at 1080p without a reference video, up from $0.57.