Add rich-text field widget (#19512)

## Context
- Extend the FIELD widget to support RICH_TEXT fields alongside existing
RELATION/MORPH_RELATION fields
- Add EDITOR display mode that renders a full rich text editor, and
FIELD display mode that shows a compact single-line preview
- Enforce mutual exclusivity: EDITOR is only available for RICH_TEXT,
CARD only for RELATION, FIELD for both
- Refactor widget configuration into a centralized FIELD_WIDGET_CONFIG
constant and shared useFieldWidgetEligibleFields hook for better
scalability. Later we might use discriminative union from graphql
scehma)

<details>
<summary>
EDITOR mode
</summary>
<img width="1095" height="731" alt="Screenshot 2026-04-09 at 17 31 41"
src="https://github.com/user-attachments/assets/cebffd0e-07ea-4f74-a3dc-ef987daa17ea"
/>
</details>
<details>
<summary>
FIELD mode
</summary>
<img width="986" height="378" alt="Screenshot 2026-04-09 at 17 35 00"
src="https://github.com/user-attachments/assets/c90a8046-fdd0-4321-8ba6-f47d89e9d42a"
/>
</details>
<details>
<summary>
Open FIELD mode
</summary>
<img width="758" height="480" alt="Screenshot 2026-04-09 at 17 35 04"
src="https://github.com/user-attachments/assets/c53cc120-0b6f-47a0-808c-27b26f9f53ec"
/>
</details>

packages/twenty-server/src/engine/metadata-modules/page-layout-widget/utils/validate-widget-configuration-input.util.ts

@@ -2,6 +2,7 @@ import { isNotEmptyObject, type ValidationError } from 'class-validator';
 
 import { AggregateChartConfigurationDTO } from 'src/engine/metadata-modules/page-layout-widget/dtos/aggregate-chart-configuration.dto';
 import { BarChartConfigurationDTO } from 'src/engine/metadata-modules/page-layout-widget/dtos/bar-chart-configuration.dto';
+import { FieldConfigurationDTO } from 'src/engine/metadata-modules/page-layout-widget/dtos/field-configuration.dto';
 import { FrontComponentConfigurationDTO } from 'src/engine/metadata-modules/page-layout-widget/dtos/front-component-configuration.dto';
 import { GaugeChartConfigurationDTO } from 'src/engine/metadata-modules/page-layout-widget/dtos/gauge-chart-configuration.dto';
 import { IframeConfigurationDTO } from 'src/engine/metadata-modules/page-layout-widget/dtos/iframe-configuration.dto';
@@ -133,10 +134,11 @@ export const validateWidgetConfigurationInput = ({
         PageLayoutWidgetExceptionCode.INVALID_PAGE_LAYOUT_WIDGET_DATA,
       );
     case WidgetConfigurationType.FIELD:
-      throw new PageLayoutWidgetException(
-        'Field configuration is not supported yet',
-        PageLayoutWidgetExceptionCode.INVALID_PAGE_LAYOUT_WIDGET_DATA,
+      errors = validateWidgetConfigurationByDto(
+        FieldConfigurationDTO,
+        configuration,
       );
+      break;
     case WidgetConfigurationType.FIELDS:
       throw new PageLayoutWidgetException(
         'Fields configuration is not supported yet',