fix: prevent localStorage bloat from derived fields on mock metadata (#18809)

## Summary

- On unauthenticated pages (login), mocked object metadata was being
hydrated into the store with `readableFields` and `updatableFields`
attached. These derived arrays duplicate every field per object,
inflating `objectMetadataItems` in localStorage from ~70 KB to ~2 MB.
Combined with other metadata keys, this exceeded Safari's 5 MB quota and
caused `QuotaExceededError`, preventing real data from replacing mock
data on login.
- Extracted flat mock data into a dedicated file
(`generatedMockObjectMetadataItemsWithRelated.ts`) and use it for store
hydration, keeping the enriched version
(`generatedMockObjectMetadataItems`) only for tests.
- Completed `splitObjectMetadataItemWithRelated`'s contract by stripping
`readableFields` and `updatableFields` at runtime (not just via
TypeScript's `Omit`), matching the `FlatObjectMetadataItem` return type
that omits all four relational properties.

## Root cause

1. `MinimalMetadataLoadEffect` loads mocked metadata on unauthenticated
pages.
2. `generatedMockObjectMetadataItems` was produced by
`enrichObjectMetadataItemsWithPermissions`, which attaches
`readableFields` and `updatableFields` (full copies of the `fields`
array).
3. `splitObjectMetadataItemWithRelated` only destructured `fields` and
`indexMetadatas` — `readableFields`/`updatableFields` leaked into
`...objectProperties` at runtime because `Omit` is a compile-time-only
guard.
4. These bloated objects were written to localStorage, consuming ~2 MB
instead of ~70 KB.
5. On login, the intermediate state (old composite mock `current` + new
flat real `draft`) exceeded the 5 MB quota, causing a
`QuotaExceededError` deadlock.

## Test plan

- [ ] Open the app in a fresh Safari private window (empty localStorage)
- [ ] Verify the login page loads without errors
- [ ] Log in and verify metadata loads correctly
- [ ] Check `localStorage` size —
`metadataStoreState__objectMetadataItems` should be ~70 KB, not ~2 MB
- [ ] Run existing tests: `npx nx test twenty-front` — no regressions
from the mock data split


Made with [Cursor](https://cursor.com)

---------

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

packages/twenty-front/src/modules/metadata-store/hooks/useLoadMockedMinimalMetadata.ts

@@ -11,11 +11,11 @@ export const useLoadMockedMinimalMetadata = () => {
   const loadMockedMinimalMetadata = useCallback(async () => {
     resetMetadataStore();
     const [
-      { generatedMockObjectMetadataItems },
+      { generatedMockObjectMetadataItemsWithRelated },
       { mockedViews },
       { mockedNavigationMenuItems },
     ] = await Promise.all([
-      import('~/testing/utils/generatedMockObjectMetadataItems'),
+      import('~/testing/utils/generatedMockObjectMetadataItemsWithRelated'),
       import('~/testing/mock-data/generated/metadata/views/mock-views-data'),
       import(
         '~/testing/mock-data/generated/metadata/navigation-menu-items/mock-navigation-menu-items-data'
@@ -23,7 +23,9 @@ export const useLoadMockedMinimalMetadata = () => {
     ]);
 
     const { flatObjects, flatFields, flatIndexes } =
-      splitObjectMetadataItemWithRelated(generatedMockObjectMetadataItems);
+      splitObjectMetadataItemWithRelated(
+        generatedMockObjectMetadataItemsWithRelated,
+      );
 
     replaceDraft('objectMetadataItems', flatObjects, MOCKED_COLLECTION_HASH);
     replaceDraft('fieldMetadataItems', flatFields, MOCKED_COLLECTION_HASH);

packages/twenty-front/src/testing/utils/generatedMockObjectMetadataItems.ts

@@ -1,15 +1,9 @@
 import { type ObjectMetadataItem } from '@/object-metadata/types/ObjectMetadataItem';
 import { enrichObjectMetadataItemsWithPermissions } from '@/object-metadata/utils/enrichObjectMetadataItemsWithPermissions';
-import { mapPaginatedObjectMetadataItemsToObjectMetadataItems } from '@/object-metadata/utils/mapPaginatedObjectMetadataItemsToObjectMetadataItems';
-import { type ObjectMetadataItemsQuery } from '~/generated-metadata/graphql';
-
-import { mockedStandardObjectMetadataQueryResult } from '~/testing/mock-data/generated/metadata/objects/mock-objects-metadata';
+import { generatedMockObjectMetadataItemsWithRelated } from '~/testing/utils/generatedMockObjectMetadataItemsWithRelated';
 
 export const generatedMockObjectMetadataItems: ObjectMetadataItem[] =
   enrichObjectMetadataItemsWithPermissions({
-    objectMetadataItems: mapPaginatedObjectMetadataItemsToObjectMetadataItems({
-      pagedObjectMetadataItems:
-        mockedStandardObjectMetadataQueryResult as unknown as ObjectMetadataItemsQuery,
-    }),
+    objectMetadataItems: generatedMockObjectMetadataItemsWithRelated,
     objectPermissionsByObjectMetadataId: {},
   });

packages/twenty-front/src/testing/utils/generatedMockObjectMetadataItemsWithRelated.ts

@@ -0,0 +1,9 @@
+import { type ObjectMetadataItemWithRelated } from '@/metadata-store/utils/splitObjectMetadataItemWithRelated';
+import { mapPaginatedObjectMetadataItemsToObjectMetadataItems } from '@/object-metadata/utils/mapPaginatedObjectMetadataItemsToObjectMetadataItems';
+
+import { mockedStandardObjectMetadataQueryResult } from '~/testing/mock-data/generated/metadata/objects/mock-objects-metadata';
+
+export const generatedMockObjectMetadataItemsWithRelated: ObjectMetadataItemWithRelated[] =
+  mapPaginatedObjectMetadataItemsToObjectMetadataItems({
+    pagedObjectMetadataItems: mockedStandardObjectMetadataQueryResult,
+  });