Factorize from entity to flat entity utils (#21972)

## What

Factorizes the two responsibilities that were copy‑pasted across every
`from-<entity>-entity-to-flat-<entity>` util into two reusable tools.

### `fromEntityToScalarEntity`
Projects a TypeORM entity into its scalar flat shape using an
**allow‑list** driven by
`ALL_ENTITY_PROPERTIES_CONFIGURATION_BY_METADATA_NAME` (plus the base
columns `id`/`workspaceId`/`applicationId`/`universalIdentifier`). Only
registered scalar columns are forwarded, `Date`s are serialized to ISO
strings, and absent values are normalized to `null`. Replaces the
previous deny‑list (`removePropertiesFromRecord`) approach, so
unregistered/deprecated columns can no longer silently leak into the
flat entity.

### `resolveManyToOneRelationIdsToUniversalIdentifiers`
Resolves an entity's many‑to‑one foreign keys to their universal
identifiers, driven by `ALL_MANY_TO_ONE_METADATA_RELATIONS`. Handles the
always‑present `application`, nullable relations, and throws a
`FlatEntityMapsException` when a referenced id is missing from its
identifier map. Mirrors `resolveUniversalRelationIdentifiersToIds` in
the opposite direction.

Each `from-<entity>` util now reduces to: scalar spread + relation
spread (+ explicit one‑to‑many id/universalIdentifier arrays where
applicable).

### Note
The allow‑list drops `isUIReadOnly` (a `WasRemovedInUpgrade` column not
in the config) from `fieldMetadata`, which is the only
integration‑snapshot change.

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packages/twenty-server/src/engine/metadata-modules/flat-skill/utils/from-skill-entity-to-flat-skill.util.ts

@@ -1,40 +1,26 @@
-import { isDefined } from 'twenty-shared/utils';
-
-import {
-  FlatEntityMapsException,
-  FlatEntityMapsExceptionCode,
-} from 'src/engine/metadata-modules/flat-entity/exceptions/flat-entity-maps.exception';
+import { fromEntityToScalarEntity } from 'src/engine/metadata-modules/flat-entity/utils/from-entity-to-scalar-entity.util';
 import { type FlatSkill } from 'src/engine/metadata-modules/flat-skill/types/flat-skill.type';
 import { type FromEntityToFlatEntityArgs } from 'src/engine/workspace-cache/types/from-entity-to-flat-entity-args.type';
+import { resolveManyToOneRelationIdsToUniversalIdentifiers } from 'src/engine/workspace-manager/workspace-migration/universal-flat-entity/utils/resolve-many-to-one-relation-ids-to-universal-identifiers.util';
 
-export const fromSkillEntityToFlatSkill = ({
-  entity: skillEntity,
-  applicationIdToUniversalIdentifierMap,
-}: FromEntityToFlatEntityArgs<'skill'>): FlatSkill => {
-  const applicationUniversalIdentifier =
-    applicationIdToUniversalIdentifierMap.get(skillEntity.applicationId);
+export const fromSkillEntityToFlatSkill = (
+  args: FromEntityToFlatEntityArgs<'skill'>,
+): FlatSkill => {
+  const { entity: skillEntity } = args;
 
-  if (!isDefined(applicationUniversalIdentifier)) {
-    throw new FlatEntityMapsException(
-      `Application with id ${skillEntity.applicationId} not found for skill ${skillEntity.id}`,
-      FlatEntityMapsExceptionCode.ENTITY_NOT_FOUND,
-    );
-  }
+  const skillScalarEntity = fromEntityToScalarEntity({
+    metadataName: 'skill',
+    entity: skillEntity,
+  });
+
+  const relationUniversalIdentifiers =
+    resolveManyToOneRelationIdsToUniversalIdentifiers({
+      metadataName: 'skill',
+      ...args,
+    });
 
   return {
-    createdAt: skillEntity.createdAt.toISOString(),
-    updatedAt: skillEntity.updatedAt.toISOString(),
-    id: skillEntity.id,
-    name: skillEntity.name,
-    label: skillEntity.label,
-    icon: skillEntity.icon,
-    description: skillEntity.description,
-    content: skillEntity.content,
-    workspaceId: skillEntity.workspaceId,
-    isCustom: skillEntity.isCustom,
-    isActive: skillEntity.isActive,
-    universalIdentifier: skillEntity.universalIdentifier,
-    applicationId: skillEntity.applicationId,
-    applicationUniversalIdentifier,
+    ...skillScalarEntity,
+    ...relationUniversalIdentifiers,
   };
 };