Morph-picker-MultiSelect-picker (#14113)

# 🚀 Multi-Select Morph Relations / One to Many

Adds **multi-select picker support** for morph relations on the **One To
Many** side, allowing users to select multiple related records from
different object types.

### 🔑 Main Changes (TL;DR)
- **New Component**: `MorphRelationOneToManyFieldInput` for
multi-selection
- **Enhanced Hooks**: `useAttachMorphRelatedRecordFromRecord` &
`useDetachMorphRelatedRecordFromRecord`
- **Better UX**: Optimistic updates, improved search, loading states
- **24 files changed**: Mostly additions (1,277 lines added, 56 removed)


**Summary**: This adds multi-select capability to morph relations with
proper state management and optimistic updates. The changes are mostly
additive and follow existing patterns.


**TODO** :
- optimistic rendering not working currently
- single select picker (many to one)

packages/twenty-front/src/modules/object-metadata/hooks/useDoObjectMetadataItemsExist.ts

@@ -0,0 +1,17 @@
+import { useRecoilValue } from 'recoil';
+
+import { objectMetadataItemsBySingularNameSelector } from '@/object-metadata/states/objectMetadataItemsBySingularNameSelector';
+
+import { isDefined } from 'twenty-shared/utils';
+
+export const useDoObjectMetadataItemsExist = (
+  objectNameSingulars: string[],
+) => {
+  const objectMetadataItems = useRecoilValue(
+    objectMetadataItemsBySingularNameSelector(objectNameSingulars),
+  );
+
+  return objectMetadataItems.every((objectMetadataItem) =>
+    isDefined(objectMetadataItem),
+  );
+};

packages/twenty-front/src/modules/object-metadata/states/objectMetadataItemsBySingularNameSelector.ts

@@ -0,0 +1,27 @@
+import { selectorFamily } from 'recoil';
+
+import { objectMetadataItemsState } from '@/object-metadata/states/objectMetadataItemsState';
+import { type ObjectMetadataItem } from '@/object-metadata/types/ObjectMetadataItem';
+import { isDefined } from 'twenty-shared/utils';
+
+export const objectMetadataItemsBySingularNameSelector = selectorFamily<
+  ObjectMetadataItem[],
+  string[]
+>({
+  key: 'objectMetadataItemsSelector',
+  get:
+    (objectNameSingulars: string[]) =>
+    ({ get }) => {
+      const objectMetadataItems = get(objectMetadataItemsState);
+
+      return objectNameSingulars
+        .map(
+          (objectNameSingular) =>
+            objectMetadataItems.find(
+              (objectMetadataItem) =>
+                objectMetadataItem.nameSingular === objectNameSingular,
+            ) ?? null,
+        )
+        .filter(isDefined);
+    },
+});