fix(web-admin): add type cast to NotificationModal initial prop

TypeScript strict check rejects NotificationItem|{} union as
Partial<CreateNotificationPayload>&{id?}. Add explicit cast to satisfy
the type checker without changing runtime behavior.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

it0-web-admin/src/app/(admin)/notifications/page.tsx

@@ -691,9 +691,9 @@ export default function NotificationsPage() {
       {modal && (
         <NotificationModal
           initial={
-            modal.mode === 'edit'
+            (modal.mode === 'edit'
               ? { ...modal.item, id: modal.item.id }
-              : {}
+              : {}) as Partial<CreateNotificationPayload> & { id?: string }
           }
           allTags={allTags}
           onSave={handleSave}