fix(directory-sync): deserialize EventDirectory timestamps to Date

createdAt/updatedAt on webhook directory event payloads were left as raw
strings while every other directory-sync serializer (REST resources and
the dsync.group.*/dsync.user.* event serializers) converts date-time
fields to Date. event-directory.* is hand-owned, so the emitter's
date-time -> new Date() rule never reached it. Bring it in line so all
directory-sync timestamps are consistently Date objects.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: gjtorikian

src/directory-sync/interfaces/event-directory.interface.ts

@@ -16,8 +16,8 @@ export interface EventDirectory {
   name: string;
   organizationId?: string;
   domains: EventDirectoryDomain[];
-  createdAt: string;
-  updatedAt: string;
+  createdAt: Date;
+  updatedAt: Date;
 }
 
 export interface EventDirectoryResponse {

src/directory-sync/serializers/event-directory.serializer.ts

@@ -17,8 +17,8 @@ export const deserializeEventDirectory = (
   name: directory.name,
   organizationId: directory.organization_id,
   domains: directory.domains,
-  createdAt: directory.created_at,
-  updatedAt: directory.updated_at,
+  createdAt: new Date(directory.created_at),
+  updatedAt: new Date(directory.updated_at),
 });
 
 export const deserializeDeletedEventDirectory = (
@@ -30,8 +30,8 @@ export const deserializeDeletedEventDirectory = (
   state: directory.state,
   name: directory.name,
   organizationId: directory.organization_id,
-  createdAt: directory.created_at,
-  updatedAt: directory.updated_at,
+  createdAt: new Date(directory.created_at),
+  updatedAt: new Date(directory.updated_at),
 });
 
 export const deserializeUpdatedEventDirectoryGroup = (