refs https://github.com/TryGhost/Product/issues/3729
- Wired up the Pintura Integration to AdminX.
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### <samp>🤖 Generated by Copilot at 4d33355</samp>
This pull request adds the ability to customize the Pintura image editor
with custom JS and CSS files in the advanced settings modal. It
introduces a new `files.ts` file in the `api` folder, which provides a
hook and a helper function for uploading and retrieving files. It also
modifies the `PinturaModal.tsx` component to use these functions and
display the settings.
