feat: add placeholderData option to ClientsPage and SessionsPage queries for improved data handling

src/pages/ClientsPage.tsx

@@ -36,6 +36,7 @@ function ClientsPage() {
         })
         .json<Client[]>(),
     enabled: !!me,
+    placeholderData: (previousData) => previousData,
   });
 
   const { data: count } = useQuery({

src/pages/SessionsPage.tsx

@@ -57,6 +57,7 @@ function SessionsPage() {
         .json<Session[]>(),
     enabled: !!me,
     select: groupByCreatedAt,
+    placeholderData: (previousData) => previousData,
   });
 
   const { data: count } = useQuery({