Loads the generated contract shared by the backend and browser packages.

The checked-in source lives at contract/letterpress-v1.json. Release tooling expands it into priv/contract.json and the TypeScript projection used by @letterpress/language and @letterpress/svelte. All projections carry the same contract version.

The decoded map is cached in :persistent_term after its first read. Treat it as immutable application data.

Example

iex> contract = Letterpress.Contract.get()
iex> {contract["contract_version"], Map.keys(contract["profiles"]) |> Enum.sort()}
{1, ["email/mjml-liquid@1", "html/liquid@1", "text/liquid@1"]}