DSL for declaring which Ash resources become generated TypeScript row types.

A host module uses this and declares each type:

defmodule MyApp.Assets.Types do
  use PhoenixAssets.Types.Schema

  type "ArticleRow",
    resource: MyApp.Content.Article,
    only: :public,
    omit: [:internal_score],
    calculations: [:like_count]
end

Options per type/2:

• :resource (required) -- the Ash resource module.
• :only -- :public (default) or :all.
• :omit -- attribute names to drop even if otherwise included.
• :expose -- non-public attribute names to add (opt-in escape hatch).
• :calculations -- calculation names to include.

Declarations are validated at compile time: a missing :resource or an unknown option is a compile error. Field-level names (:expose, :calculations) are checked at generation time against the resource, which raises a clear error for unknown names.