Feature: #107471 - New scheduler task wizard

Description

A wizard to create new scheduler tasks has been introduced in the System > Scheduler module to significantly improve the user experience when creating new scheduler tasks. The wizard replaces the previous dropdown-based task selection in FormEngine with a modern, categorized interface similar to the content element wizard.

UX Improvements

Categorized task selection: Tasks are now organized by extension/category for better discoverability
Search functionality: Users can search and filter available tasks
Visual task representation: Each task displays with proper icons, titles, and descriptions

Tip

Using the iconOverlay option on task type registration, an icon overlay can be added, which is then displayed in the wizard. This can be useful for similar task types that use the same "base" icon, but still have to be differentiated.

Technical Improvements

Prevents broken records: The old system pre-selected the first available task type when creating new tasks, which caused validation issues when users changed the task type since required fields for the new type might not be properly initialized
Clean task type pre-selection: Selected task type is directly passed to FormEngine, eliminating the need to change the type in the form
Extensible via PSR-14 event: Extensions can modify wizard items through the new ModifyNewSchedulerTaskWizardItemsEvent

PSR-14 Event

A new PSR-14 event \TYPO3\CMS\Scheduler\Event\ModifyNewSchedulerTaskWizardItemsEvent has been introduced to allow extensions to modify the wizard items.

The event provides the following methods:

getWizardItems(): Returns the current wizard items array
setWizardItems(): Sets the complete wizard items array
addWizardItem(): Adds a single wizard item
removeWizardItem(): Removes a wizard item by key
getRequest(): Returns the current server request

Example

A corresponding event listener class:

<?php

namespace Vendor\MyExtension\EventListener;

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Scheduler\Event\ModifyNewSchedulerTaskWizardItemsEvent;

final class ModifySchedulerTaskWizardListener
{
    #[AsEventListener('my-extension/scheduler/modify-wizard-items')]
    public function __invoke(ModifyNewSchedulerTaskWizardItemsEvent $event): void
    {
        // Add a custom task to the wizard
        $event->addWizardItem('my_custom_task', [
            'title' => 'My Custom Task',
            'description' => 'A custom task provided by my extension',
            'iconIdentifier' => 'my-custom-icon',
            'taskType' => 'MyVendor\\MyExtension\\Task\\CustomTask',
            'taskClass' => 'MyVendor\\MyExtension\\Task\\CustomTask',
        ]);

        // Remove an existing task
        $event->removeWizardItem('redirects_redirects:checkintegrity');

        // Modify existing wizard items
        $wizardItems = $event->getWizardItems();
        foreach ($wizardItems as $key => $item) {
            if (isset($item['title']) && str_contains($item['title'], 'referenceindex:update')) {
                $item['title'] = 'Update reference index';
                $event->addWizardItem($key, $item);
            }
        }
    }
}

Impact

The scheduler task creation workflow is significantly improved with better UX
Risk of creating broken task records due to task type changes is eliminated
Extensions can easily modify the wizard through the PSR-14 event
The interface is more consistent with other TYPO3 wizard interfaces
Task discovery is improved through categorization and search functionality