fix(server): allow relabelling onto a field introduced in the same manifest sync (#22727)

## Context

Closes twentyhq/core-team-issues#2655.

`computeOrderedMigrationActions` runs `objectMetadata.update` **before**
`fieldMetadata.create`. In a single manifest sync that both introduces a
new field and relabels the object's
`labelIdentifierFieldMetadataUniversalIdentifier` onto that field, the
object update handler resolved the label identifier's universal
identifier against the persisted `flatFieldMetadataMaps` only. Since the
field's `fieldMetadata.create` runs later in the same migration, the
field isn't in the maps yet and the sync failed with `ENTITY_NOT_FOUND`.

The API metadata path is unaffected because create-field and
update-object are separate requests (separate transactions), so the
field is already persisted by the time the object update resolves.

## What this does

`update-object-action-handler.service.ts` now resolves
`labelIdentifierFieldMetadataId` and `imageIdentifierFieldMetadataId`
against the deterministically preallocated field ids first, then falls
back to the persisted flat maps for fields that already exist.

The preallocated ids
(`preallocatedIdByUniversalIdentifierByMetadataName`) are built from
every create action before the migration loop starts
(`buildPreallocatedIdByUniversalIdentifierFromActions`) and are the same
ids `create-field-action-handler` persists the fields with. This is the
same "preallocated-first, then flat maps" resolution that
`resolveUniversalRelationIdentifiersToIds` already uses for modeled
many-to-one relations, so no ordering change or new machinery is needed,
and the single sync stays one atomic transaction.

This does not touch the underlying action ordering or the hand-rolled
label/image identifier handling flagged by the `#2172` TODO;
generalizing those into the relation config remains the follow-up.

## Test

Adds `relabel-onto-new-field-manifest-sync.integration-spec.ts` (used as
the TDD reproduction, now green):
- introducing a field and relabelling onto it in a single sync succeeds,
and the object's `labelIdentifierFieldMetadataId` points at the new
field;
- the split path (introduce in one sync, relabel in the next) still
succeeds and exposes the enriched `labelIdentifierFieldMetadataId`
through the metadata API.

Both cases pass against the fix. `oxlint`, `oxfmt`, and `typecheck` are
clean.

---
_Generated by [Claude
Code](https://claude.ai/code/session_01KJewXMuWYUyrX3YJh2JBDE)_

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packages/twenty-server/src/engine/workspace-manager/workspace-migration/workspace-migration-runner/action-handlers/object/services/update-object-action-handler.service.ts

@@ -67,35 +67,21 @@ export class UpdateObjectActionHandlerService extends WorkspaceMigrationRunnerAc
     };
 
     if (isDefined(labelIdentifierFieldMetadataUniversalIdentifier)) {
-      const flatFieldMetadata = findFlatEntityByUniversalIdentifier({
-        flatEntityMaps: allFlatEntityMaps.flatFieldMetadataMaps,
-        universalIdentifier: labelIdentifierFieldMetadataUniversalIdentifier,
-      });
-
-      if (!isDefined(flatFieldMetadata)) {
-        throw new FlatEntityMapsException(
-          `Could not resolve labelIdentifierFieldMetadataUniversalIdentifier to labelIdentifierFieldMetadataId: no fieldMetadata found for universal identifier ${labelIdentifierFieldMetadataUniversalIdentifier}`,
-          FlatEntityMapsExceptionCode.ENTITY_NOT_FOUND,
-        );
-      }
-
-      transpiledUpdate.labelIdentifierFieldMetadataId = flatFieldMetadata.id;
+      transpiledUpdate.labelIdentifierFieldMetadataId =
+        this.resolveFieldMetadataIdOrThrow({
+          context,
+          universalIdentifier: labelIdentifierFieldMetadataUniversalIdentifier,
+          foreignKeyName: 'labelIdentifierFieldMetadataId',
+        });
     }
 
     if (isDefined(imageIdentifierFieldMetadataUniversalIdentifier)) {
-      const flatFieldMetadata = findFlatEntityByUniversalIdentifier({
-        flatEntityMaps: allFlatEntityMaps.flatFieldMetadataMaps,
-        universalIdentifier: imageIdentifierFieldMetadataUniversalIdentifier,
-      });
-
-      if (!isDefined(flatFieldMetadata)) {
-        throw new FlatEntityMapsException(
-          `Could not resolve imageIdentifierFieldMetadataUniversalIdentifier to imageIdentifierFieldMetadataId: no fieldMetadata found for universal identifier ${imageIdentifierFieldMetadataUniversalIdentifier}`,
-          FlatEntityMapsExceptionCode.ENTITY_NOT_FOUND,
-        );
-      }
-
-      transpiledUpdate.imageIdentifierFieldMetadataId = flatFieldMetadata.id;
+      transpiledUpdate.imageIdentifierFieldMetadataId =
+        this.resolveFieldMetadataIdOrThrow({
+          context,
+          universalIdentifier: imageIdentifierFieldMetadataUniversalIdentifier,
+          foreignKeyName: 'imageIdentifierFieldMetadataId',
+        });
     }
 
     return {
@@ -106,6 +92,44 @@ export class UpdateObjectActionHandlerService extends WorkspaceMigrationRunnerAc
     };
   }
 
+  private resolveFieldMetadataIdOrThrow({
+    context,
+    universalIdentifier,
+    foreignKeyName,
+  }: {
+    context: WorkspaceMigrationActionRunnerArgs<UniversalUpdateObjectAction>;
+    universalIdentifier: string;
+    foreignKeyName: string;
+  }): string {
+    const {
+      allFlatEntityMaps,
+      preallocatedIdByUniversalIdentifierByMetadataName,
+    } = context;
+
+    const preallocatedFieldMetadataId =
+      preallocatedIdByUniversalIdentifierByMetadataName?.fieldMetadata?.[
+        universalIdentifier
+      ];
+
+    if (isDefined(preallocatedFieldMetadataId)) {
+      return preallocatedFieldMetadataId;
+    }
+
+    const flatFieldMetadata = findFlatEntityByUniversalIdentifier({
+      flatEntityMaps: allFlatEntityMaps.flatFieldMetadataMaps,
+      universalIdentifier,
+    });
+
+    if (!isDefined(flatFieldMetadata)) {
+      throw new FlatEntityMapsException(
+        `Could not resolve ${foreignKeyName}: no fieldMetadata found for universal identifier ${universalIdentifier}`,
+        FlatEntityMapsExceptionCode.ENTITY_NOT_FOUND,
+      );
+    }
+
+    return flatFieldMetadata.id;
+  }
+
   async executeForMetadata(
     context: WorkspaceMigrationActionRunnerContext<FlatUpdateObjectAction>,
   ): Promise<void> {