fix: deleted jobs reappear after clearing filters

onDelete was removing the job from jobList but not from backup.
When filters were cleared, the useEffect re-derived jobList from
the stale backup, re-populating the deleted job.

Author: wicky-zipstack

frontend/src/ide/scheduler/JobList.jsx

@@ -237,8 +237,12 @@ const JobList = () => {
       await deleteTask(delTaskDetail.projectId, delTaskDetail.taskId);
       setIsDeleteModalOpen(false);
       notify({ type: "success", message: "Job deleted successfully" });
-      setJobList(
-        jobList.filter(
+      const remaining = jobList.filter(
+        (el) => el.periodic_task_details.id !== delTaskDetail.taskId
+      );
+      setJobList(remaining);
+      setBackup((prev) =>
+        prev.filter(
           (el) => el.periodic_task_details.id !== delTaskDetail.taskId
         )
       );