Support per-asset focal point and template-imposed cropping via the Frontify Media Processing API (with automatic WebP)

Problem/Motivation

The field/formatter currently renders original asset URLs. There is no way to (a) store a per-asset focal point chosen by the editor, and (b) let the theme impose an aspect-ratio crop that respects that focal point - the equivalent of core image styles + focal_point, but computed by Frontify's own Media Processing API instead of re-hosting derivatives in Drupal.

Proposed resolution

• Store per-asset focus point and source dimensions on the field (schema + widget storage).
• At render time, compute a focal-window crop from the requested style box + stored focus (with zoom factor), request it through the Media Processing API, and emit WebP automatically.

We run this in production as a composer patch against 3.0.1 (Drupal 11, PHP 8.4) and would like to upstream the capability; the patch is large, so the first step is agreeing on the direction and splitting reviewable MRs (schema first).