perf: use cache for role validation (#23383)

## Context

Role assignment validation queried PostgreSQL only to check whether a
role exists and whether `canBeAssignedToUsers` is enabled. Both values
already exist in `flatRoleMaps`.

This validation runs when inviting users and assigning a role to a user
workspace.

## What changed

- Replace the role repository lookup with `flatRoleMaps`
- Resolve the role through the existing keyed flat-map helper
- Preserve the existing role-not-found and role-not-assignable errors
- Replace unused TypeORM module wiring with the flat entity cache module

## Expected impact

On a warm workspace cache, role assignment validation uses an O(1) map
lookup and avoids a PostgreSQL round trip. Cold caches retain the normal
workspace cache recomputation behavior.

## Validation

- Typecheck reports no errors in the changed files
- Existing validation outcomes and exception codes are preserved

<!-- This is an auto-generated description by cubic. -->
<a
href="https://cubic.dev/pr/twentyhq/twenty/pull/23383?utm_source=github"
target="_blank" rel="noopener noreferrer"
data-no-image-dialog="true"><picture><source
media="(prefers-color-scheme: dark)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"><source
media="(prefers-color-scheme: light)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-light.svg"><img
alt="Review in cubic"
src="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"></picture></a>
<!-- End of auto-generated description by cubic. -->

packages/twenty-server/src/engine/metadata-modules/role-validation/role-validation.module.ts

@@ -1,16 +1,10 @@
 import { Module } from '@nestjs/common';
-import { TypeOrmModule } from '@nestjs/typeorm';
-
-import { RoleEntity } from 'src/engine/metadata-modules/role/role.entity';
+import { WorkspaceManyOrAllFlatEntityMapsCacheModule } from 'src/engine/metadata-modules/flat-entity/services/workspace-many-or-all-flat-entity-maps-cache.module';
 import { RoleValidationService } from 'src/engine/metadata-modules/role-validation/services/role-validation.service';
-import { provideWorkspaceScopedRepository } from 'src/engine/twenty-orm/workspace-scoped-repository/provide-workspace-scoped-repository';
 
 @Module({
-  imports: [TypeOrmModule.forFeature([RoleEntity])],
-  providers: [
-    RoleValidationService,
-    provideWorkspaceScopedRepository(RoleEntity),
-  ],
+  imports: [WorkspaceManyOrAllFlatEntityMapsCacheModule],
+  providers: [RoleValidationService],
   exports: [RoleValidationService],
 })
 export class RoleValidationModule {}

packages/twenty-server/src/engine/metadata-modules/role-validation/services/role-validation.service.ts

@@ -5,25 +5,29 @@ import {
   PermissionsExceptionCode,
   PermissionsExceptionMessage,
 } from 'src/engine/metadata-modules/permissions/permissions.exception';
-import { RoleEntity } from 'src/engine/metadata-modules/role/role.entity';
-import { InjectWorkspaceScopedRepository } from 'src/engine/twenty-orm/workspace-scoped-repository/inject-workspace-scoped-repository.decorator';
-import { WorkspaceScopedRepository } from 'src/engine/twenty-orm/workspace-scoped-repository/workspace-scoped-repository';
+import { WorkspaceManyOrAllFlatEntityMapsCacheService } from 'src/engine/metadata-modules/flat-entity/services/workspace-many-or-all-flat-entity-maps-cache.service';
+import { findFlatEntityByIdInFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/utils/find-flat-entity-by-id-in-flat-entity-maps.util';
 
 @Injectable()
 export class RoleValidationService {
   constructor(
-    @InjectWorkspaceScopedRepository(RoleEntity)
-    private readonly roleRepository: WorkspaceScopedRepository<RoleEntity>,
+    private readonly flatEntityMapsCacheService: WorkspaceManyOrAllFlatEntityMapsCacheService,
   ) {}
 
   async validateRoleAssignableToUsersOrThrow(
     roleId: string,
     workspaceId: string,
   ): Promise<void> {
-    const role = await this.roleRepository.findOne(workspaceId, {
-      where: {
-        id: roleId,
-      },
+    const { flatRoleMaps } =
+      await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
+        {
+          workspaceId,
+          flatMapsKeys: ['flatRoleMaps'],
+        },
+      );
+    const role = findFlatEntityByIdInFlatEntityMaps({
+      flatEntityId: roleId,
+      flatEntityMaps: flatRoleMaps,
     });
 
     if (!role) {