Feature: #94886 - Show selected item counts in FormEngine 

See forge#94886

Description 

The backend FormEngine now displays a compact badge for fields configured via TCA types and renderTypes when they use item count validation rules such as minItems and maxItems.

The badge reflects the currently selected number of items and the configured minimum or maximum values, and it updates automatically when entries are added or removed. This improves the visibility of selection limits for supported field types including select, category, group, folder and inline elements.

When the maximum allowed number of items is reached, the max-items notice continues to be shown as before. If a field requires a minimum number of selected items, the badge also indicates that the current selection has not yet reached the required value.

Impact 

Editors get immediate visual feedback about how many items are currently selected in relation to the configured minItems and maxItems limits. The badge is injected on the client side for any field exposing item count validation rules, so it also applies to custom render types without requiring additional PHP code.