Introducing view field group syncable entity (#17867)

## Context
Introduces a new viewFieldGroup entity that allows grouping view fields
into sections (e.g. "General", "Additional", "Other") within a view.

The page layout fields widget needs a way to organize fields into
sections. Today, views have no concept of field grouping. This PR
introduces the viewFieldGroup entity which sits between a view and its
viewFields, enabling section-based organization.

<img width="401" height="724" alt="Layout - V2 (customize visibility)"
src="https://github.com/user-attachments/assets/6376e2ab-44db-42bf-9d2c-758f56f6b548"
/>

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-server/src/engine/metadata-modules/view/dtos/view.dto.ts

@@ -4,6 +4,7 @@ import { IDField } from '@ptc-org/nestjs-query-graphql';
 
 import { AggregateOperations } from 'src/engine/api/graphql/graphql-query-runner/constants/aggregate-operations.constant';
 import { UUIDScalarType } from 'src/engine/api/graphql/workspace-schema-builder/graphql-types/scalars';
+import { ViewFieldGroupDTO } from 'src/engine/metadata-modules/view-field-group/dtos/view-field-group.dto';
 import { ViewFieldDTO } from 'src/engine/metadata-modules/view-field/dtos/view-field.dto';
 import { ViewFilterGroupDTO } from 'src/engine/metadata-modules/view-filter-group/dtos/view-filter-group.dto';
 import { ViewFilterDTO } from 'src/engine/metadata-modules/view-filter/dtos/view-filter.dto';
@@ -104,6 +105,9 @@ export class ViewDTO {
   @Field(() => [ViewGroupDTO])
   viewGroups?: ViewGroupDTO[];
 
+  @Field(() => [ViewFieldGroupDTO])
+  viewFieldGroups?: ViewFieldGroupDTO[];
+
   @Field(() => ViewVisibility, {
     nullable: false,
   })