[REQUIRES_FULL_CACHE_FLUSH_WHEN_RELEASED] Refactor FlatEntity to be UniversalFlatEntity superset (#17452)

# Introduction
In this PR we're refactoring the `FlatEntity` type to become a superset
of the `UniversalFlatEntity`.
Right now we're storing all the extra properties in `__universal`
property, at some point it might just be sibling to other entity and we
might rely on the `propertiesToCompare` constants and TypeScript
allowing passing a superset type into a smaller subset type

## FromTo utils
The entity to flat entity method now computes the universal information,
standardized a typing and pattern to do

## Example
Also strictly type
```ts
    "bbb019ea-6205-498c-aea5-67bc53bce8a9": {
      "workspaceId": "20202020-1c25-4d02-bf25-6aeccf7ea419",
      "universalIdentifier": "20202020-d111-4d11-8d11-da5ab0a11002",
      "applicationId": "d01b010d-b984-465b-b40b-370e954e5188",
      "id": "bbb019ea-6205-498c-aea5-67bc53bce8a9",
      "pageLayoutTabId": "791a512f-169f-4209-b731-aa86716668c6",
      "title": "Deals by Company",
      "type": "GRAPH",
      "objectMetadataId": "9e14efea-df5b-4c0e-aba9-cfe455f32397",
      "gridPosition": { "row": 0, "column": 6, "rowSpan": 6, "columnSpan": 6 },
      "configuration": {
        "color": "orange",
        "orderBy": "FIELD_ASC",
        "timezone": "UTC",
        "displayLegend": true,
        "displayDataLabel": false,
        "showCenterMetric": true,
        "configurationType": "PIE_CHART",
        "firstDayOfTheWeek": 0,
        "aggregateOperation": "COUNT",
        "groupBySubFieldName": "name",
        "groupByFieldMetadataId": "6673ff18-63d2-47a1-8f85-2b9b09ca27a5",
        "aggregateFieldMetadataId": "8d64ee41-5dd4-4de6-945a-7c0c18399715"
      },
      "createdAt": "2026-01-28T14:08:52.140Z",
      "updatedAt": "2026-01-28T14:08:52.140Z",
      "deletedAt": null,
      "__universal": {
        "universalIdentifier": "20202020-d111-4d11-8d11-da5ab0a11002",
        "applicationUniversalIdentifier": "20202020-64aa-4b6f-b003-9c74b97cee20",
        "pageLayoutTabUniversalIdentifier": "20202020-d011-4d11-8d11-da5ab0a01001",
        "objectMetadataUniversalIdentifier": "20202020-9549-49dd-b2b2-883999db8938",
        "gridPosition": {
          "row": 0,
          "column": 6,
          "rowSpan": 6,
          "columnSpan": 6
        },
        "configuration": {
          "color": "orange",
          "orderBy": "FIELD_ASC",
          "timezone": "UTC",
          "displayLegend": true,
          "displayDataLabel": false,
          "showCenterMetric": true,
          "configurationType": "PIE_CHART",
          "firstDayOfTheWeek": 0,
          "aggregateOperation": "COUNT",
          "groupBySubFieldName": "name",
          "aggregateFieldMetadataUniversalIdentifier": "20202020-d01a-4131-8a31-f123456789ab",
          "groupByFieldMetadataUniversalIdentifier": "20202020-cbac-457e-b565-adece5fc815f"
        }
      }
    },
```

packages/twenty-server/src/engine/metadata-modules/object-metadata/object-metadata.entity.ts

@@ -11,7 +11,6 @@ import {
   UpdateDateColumn,
 } from 'typeorm';
 
-import { type JsonbProperty } from 'src/engine/workspace-manager/workspace-migration/universal-flat-entity/types/jsonb-property.type';
 import { type WorkspaceEntityDuplicateCriteria } from 'src/engine/api/graphql/workspace-query-builder/types/workspace-entity-duplicate-criteria.type';
 import { DataSourceEntity } from 'src/engine/metadata-modules/data-source/data-source.entity';
 import { FieldMetadataEntity } from 'src/engine/metadata-modules/field-metadata/field-metadata.entity';
@@ -21,6 +20,7 @@ import { FieldPermissionEntity } from 'src/engine/metadata-modules/object-permis
 import { ObjectPermissionEntity } from 'src/engine/metadata-modules/object-permission/object-permission.entity';
 import { ViewEntity } from 'src/engine/metadata-modules/view/entities/view.entity';
 import { SyncableEntity } from 'src/engine/workspace-manager/types/syncable-entity.interface';
+import { type JsonbProperty } from 'src/engine/workspace-manager/workspace-migration/universal-flat-entity/types/jsonb-property.type';
 
 @Entity('objectMetadata')
 @Unique('IDX_OBJECT_METADATA_NAME_SINGULAR_WORKSPACE_ID_UNIQUE', [
@@ -100,6 +100,7 @@ export class ObjectMetadataEntity
   shortcut: string | null;
 
   // TODO: This should not be nullable - legacy field introduced when label identifier was nullable
+  // TODO: This should be a joinColumn and we should have a FK on this too
   @Column({ nullable: true, type: 'uuid' })
   labelIdentifierFieldMetadataId: string | null;