Fix rolesPermissions cache query cartesian product (62k → 162 rows) (#19511)

## Summary
- **Split the `rolesPermissions` cache query into parallel queries** to
eliminate a 5-way LEFT JOIN cartesian product. A workspace with a role
having 5 objectPermissions × 4 permissionFlags × 124 fieldPermissions ×
5 RLP predicates × 5 RLP groups was returning 62,000 rows from just ~162
distinct records, causing 10s+ query timeouts on view updates.
- **Added missing `roleId` index on `permissionFlag` table** — the only
permission table without one, which was causing sequential scans on the
JOIN.

packages/twenty-server/src/engine/workspace-cache/utils/regroup-entities-by-related-entity-id.ts

@@ -17,7 +17,7 @@ export const regroupEntitiesByRelatedEntityId = <T extends AllMetadataName>({
   entities,
   foreignKey,
 }: RegroupEntitiesByRelatedEntityIdArgs<T>) => {
-  const entitiesByRelatedEntityId = new Map<string, RegroupedEntity[]>();
+  const entitiesByRelatedEntityId = new Map<string, MetadataEntity<T>[]>();
 
   for (const entity of entities) {
     const currentRelatedEntityId = entity[
@@ -32,10 +32,7 @@ export const regroupEntitiesByRelatedEntityId = <T extends AllMetadataName>({
       entitiesByRelatedEntityId.set(currentRelatedEntityId, []);
     }
 
-    entitiesByRelatedEntityId.get(currentRelatedEntityId)!.push({
-      id: entity.id,
-      universalIdentifier: entity.universalIdentifier,
-    });
+    entitiesByRelatedEntityId.get(currentRelatedEntityId)!.push(entity);
   }
 
   return entitiesByRelatedEntityId;