feat(code): do not show task list empty state until fetch is complete (#1924)

## Problem

when launching the app, the task list instantly shows the empty state, _then_ transitions to the loading state, creating a weird UX flash of the empty state when we don't actually know if it's empty yet

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## Changes

updates so we don't show the empty state til the fetch is done

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## How did you test this?

manually

Author: adboio

apps/code/src/renderer/features/sidebar/hooks/useSidebarData.ts

@@ -79,13 +79,13 @@ export function useSidebarData({
   activeView,
 }: UseSidebarDataProps): SidebarData {
   const showAllUsers = useSidebarStore((state) => state.showAllUsers);
-  const { data: rawTasks = [], isLoading: isLoadingTasks } = useTasks({
+  const { data: rawTasks = [], isFetched: isTasksFetched } = useTasks({
     showAllUsers,
   });
   const { data: workspaces, isFetched: isWorkspacesFetched } = useWorkspaces();
   const archivedTaskIds = useArchivedTaskIds();
   const suspendedTaskIds = useSuspendedTaskIds();
-  const isLoading = isLoadingTasks || !isWorkspacesFetched;
+  const isLoading = !isTasksFetched || !isWorkspacesFetched;
   const allTasks = useMemo(
     () =>
       rawTasks.filter(