fix(tasks): fix sidebar tasks skeleton hanging indefinitely

Switch useTasks to skipToken + keepPreviousData and derive tasksLoading
from isLoading (isPending && isFetching) instead of data presence.
This matches the established useWorkflows pattern and prevents the
skeleton from hanging forever on query errors or when workspaceId
is temporarily absent.

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/w/components/sidebar/sidebar.tsx

@@ -790,8 +790,7 @@ export const Sidebar = memo(function Sidebar() {
     )
   }
 
-  const { data: fetchedTasks } = useTasks(workspaceId)
-  const tasksLoading = fetchedTasks === undefined
+  const { data: fetchedTasks, isLoading: tasksLoading } = useTasks(workspaceId)
 
   useTaskEvents(workspaceId)
 

apps/sim/hooks/queries/tasks.ts

@@ -1,4 +1,10 @@
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import {
+  keepPreviousData,
+  skipToken,
+  useMutation,
+  useQuery,
+  useQueryClient,
+} from '@tanstack/react-query'
 import { requestJson } from '@/lib/api/client/request'
 import {
   addMothershipChatResourceContract,
@@ -210,8 +216,8 @@ export async function fetchTasks(
 export function useTasks(workspaceId?: string) {
   return useQuery({
     queryKey: taskKeys.list(workspaceId),
-    queryFn: ({ signal }) => fetchTasks(workspaceId as string, signal),
-    enabled: Boolean(workspaceId),
+    queryFn: workspaceId ? ({ signal }) => fetchTasks(workspaceId, signal) : skipToken,
+    placeholderData: keepPreviousData,
     staleTime: 60 * 1000,
   })
 }