Feature: #107036 - Configurable dashboard widgets 

Description 

Dashboard widgets can now be configured on a per-instance level using the Settings API. This allows widget authors to define settings that editors can modify directly from the dashboard interface, making widgets more flexible and adaptable to different use cases.

Typical configuration options include URLs for RSS feeds, limits on displayed items, or categories for filtering content.

Each widget instance maintains its own configuration, enabling multiple instances of the same widget type with different settings on the same or different dashboards.

Impact 

For editors

• Dashboard widgets now display a settings (cog) icon when configuration is supported.
• Clicking the icon opens a modal dialog with configurable options.
• Settings are applied immediately after saving, and the widget refreshes automatically.
• Each widget instance is configured independently per user.

For integrators

• Dashboard widgets can now expose user-configurable options.
• Settings are validated using the existing Settings API type system.
• Widget instances maintain independent configurations, allowing flexible layouts.
• No extra configuration is required—configurable widgets automatically show the settings icon.

For widget authors

• Widgets can migrate from WidgetInterface to WidgetRendererInterface to define settings and use configured values during rendering.
• Settings are validated and processed automatically via the Settings API.
• The widget context provides a Settings object containing the current configuration.
• All existing Settings API types are supported (string, int, bool, url, etc.).

<?php

use TYPO3\CMS\Core\Settings\SettingDefinition;
use TYPO3\CMS\Dashboard\Widgets\WidgetContext;
use TYPO3\CMS\Dashboard\Widgets\WidgetRendererInterface;
use TYPO3\CMS\Dashboard\Widgets\WidgetResult;

class ConfigurableWidget implements WidgetRendererInterface
{
    public function getSettingsDefinitions(): array
    {
        return [
            new SettingDefinition(
                key: 'title',
                type: 'string',
                default: 'Default Title',
                label: 'my_extension.my_widget:settings.label',
                description: 'my_extension.my_widget:settings.description.label',
            ),
            new SettingDefinition(
                key: 'limit',
                type: 'int',
                default: 10,
                label: 'my_extension.my_widget:settings.limit',
                description: 'my_extension.my_widget:settings.description.limit',
            ),
        ];
    }

    public function renderWidget(WidgetContext $context): WidgetResult
    {
        $settings = $context->settings;
        $title = $settings->get('title');
        $limit = $settings->get('limit');

        // Use settings to customize widget output
        return new WidgetResult(
            label: $title,
            content: '<!-- widget content -->',
            refreshable: true
        );
    }
}