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/resolvers/view.resolver.ts

@@ -11,19 +11,20 @@ import {
 import { isArray } from '@sniptt/guards';
 import { isDefined } from 'twenty-shared/utils';
 
+import { MetadataResolver } from 'src/engine/api/graphql/graphql-config/decorators/metadata-resolver.decorator';
 import { I18nService } from 'src/engine/core-modules/i18n/i18n.service';
 import { type I18nContext } from 'src/engine/core-modules/i18n/types/i18n-context.type';
 import { WorkspaceEntity } from 'src/engine/core-modules/workspace/workspace.entity';
 import { type IDataloaders } from 'src/engine/dataloaders/dataloader.interface';
 import { AuthUserWorkspaceId } from 'src/engine/decorators/auth/auth-user-workspace-id.decorator';
 import { AuthWorkspace } from 'src/engine/decorators/auth/auth-workspace.decorator';
-import { MetadataResolver } from 'src/engine/api/graphql/graphql-config/decorators/metadata-resolver.decorator';
 import { CustomPermissionGuard } from 'src/engine/guards/custom-permission.guard';
 import { NoPermissionGuard } from 'src/engine/guards/no-permission.guard';
 import { WorkspaceAuthGuard } from 'src/engine/guards/workspace-auth.guard';
 import { resolveObjectMetadataStandardOverride } from 'src/engine/metadata-modules/object-metadata/utils/resolve-object-metadata-standard-override.util';
+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 { ViewFieldV2Service } from 'src/engine/metadata-modules/view-field/services/view-field-v2.service';
+import { ViewFieldService } from 'src/engine/metadata-modules/view-field/services/view-field.service';
 import { ViewFilterGroupDTO } from 'src/engine/metadata-modules/view-filter-group/dtos/view-filter-group.dto';
 import { ViewFilterGroupService } from 'src/engine/metadata-modules/view-filter-group/services/view-filter-group.service';
 import { ViewFilterDTO } from 'src/engine/metadata-modules/view-filter/dtos/view-filter.dto';
@@ -56,7 +57,7 @@ export class ViewResolver {
     private readonly viewGroupService: ViewGroupService,
     private readonly i18nService: I18nService,
 
-    private readonly viewFieldV2Service: ViewFieldV2Service,
+    private readonly viewFieldService: ViewFieldService,
   ) {}
 
   @ResolveField(() => String)
@@ -209,7 +210,7 @@ export class ViewResolver {
       return view.viewFields;
     }
 
-    return this.viewFieldV2Service.findByViewId(workspace.id, view.id);
+    return this.viewFieldService.findByViewId(workspace.id, view.id);
   }
 
   @ResolveField(() => [ViewFilterDTO])
@@ -259,4 +260,20 @@ export class ViewResolver {
 
     return this.viewGroupService.findByViewId(workspace.id, view.id);
   }
+
+  @ResolveField(() => [ViewFieldGroupDTO])
+  async viewFieldGroups(
+    @Parent() view: ViewDTO,
+    @Context() context: { loaders: IDataloaders },
+    @AuthWorkspace() workspace: WorkspaceEntity,
+  ) {
+    if (isArray(view.viewFieldGroups)) {
+      return view.viewFieldGroups;
+    }
+
+    return context.loaders.viewFieldGroupsByViewIdLoader.load({
+      workspaceId: workspace.id,
+      viewId: view.id,
+    });
+  }
 }