Feature: #108992 - New PSR-14 event for workspace dependency resolution 

Description 

A new PSR-14 event \TYPO3\CMS\Workspaces\Event\IsReferenceConsideredForDependencyEvent has been added. It is dispatched for each sys_refindex row when the workspace dependency resolver evaluates which references constitute structural dependencies during publish, stage, discard, and display operations.

Listeners decide whether a particular reference should be treated as a workspace dependency. References are opt-in: the default is "not a dependency", and listeners must explicitly mark relevant references.

The event has the following methods:

• getTableName(): The table owning the field ( sys_refindex.tablename).
• getRecordId(): The record owning the field ( sys_refindex.recuid).
• getFieldName(): The TCA field name ( sys_refindex.field).
• getReferenceTable(): The referenced table ( sys_refindex.ref_table).
• getReferenceId(): The referenced record ID ( sys_refindex.ref_uid).
• getAction(): The \TYPO3\CMS\Workspaces\Dependency\DependencyCollectionAction enum value ( Publish, StageChange, Discard, or Display).
• getWorkspaceId(): The current workspace ID.
• isDependency() / setDependency(): Read or change whether this reference is a structural dependency.

TYPO3 Core registers a listener that marks type=inline, type=file (with foreign_field), and type=flex fields as dependencies.

A new enum \TYPO3\CMS\Workspaces\Dependency\DependencyCollectionAction has been added to represent the action context.

Example 

A third-party extension that stores parent-child relationships in a custom field can register a listener to include those references as workspace dependencies:

namespace Vendor\MyPackage\EventListener;

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Workspaces\Event\
    IsReferenceConsideredForDependencyEvent;

#[AsEventListener('my-package/workspace-dependency')]
final class WorkspaceDependencyListener
{
    public function __invoke(
        IsReferenceConsideredForDependencyEvent $event
    ): void {
        if ($event->getFieldName() === 'tx_mypackage_parent') {
            $event->setDependency(true);
        }
    }
}

Impact 

Extensions can now register custom parent-child relationships as workspace dependencies via this PSR-14 event. This ensures that structurally dependent records are published, staged, or discarded together, preventing orphaned records in workspaces.

The internal pseudo-event mechanism (EventCallback, ElementEntityProcessor) that was previously used has been removed. This is an internal change that does not affect the public API.