Breaking: #107403 - Remove LocalPreviewHelper + LocalCropScaleMaskHelper 

See forge#107403

Description 

The helper classes for preview and CropScaleMask (CSM) image generation prevented further unification of the File Abstraction Layer (FAL) image processing API.

The two helper classes \TYPO3\CMS\Core\Resource\Processing\LocalPreviewHelper and \TYPO3\CMS\Core\Resource\Processing\LocalCropScaleMaskHelper have been removed. Their functionality has been merged into \TYPO3\CMS\Core\Resource\Processing\LocalImageProcessor .

These helper classes existed for historical reasons and were never intended to be part of the public API.

Impact 

Any code that extends or references \LocalPreviewHelper or \LocalCropScaleMaskHelper will now trigger PHP fatal errors.

Affected installations 

Installations with custom extensions that extend or reference either \LocalPreviewHelper or \LocalCropScaleMaskHelper are affected and will cause PHP fatal errors.

These helper classes were meant to be internal but were never declared as such. Implementations using them directly instead of the LocalImageProcessor should be very rare.

Migration 

Remove all references to \LocalPreviewHelper or \LocalCropScaleMaskHelper from your code.

Use the LocalImageProcessor directly instead, or implement a custom image processor that executes before this processor to apply additional functionality.