feat: add CronDeleteDialog component and integrate it into CronPage for job deletion

- Implemented a new CronDeleteDialog component for confirming job deletions.
- Integrated the CronDeleteDialog into the CronPage, allowing users to delete cron jobs with confirmation.
- Refactored job deletion logic to handle state updates and loading indicators during deletion.
- Removed unused delivery channel related code from CronPage and CronTaskDialog.
- Cleaned up chat store session deletion logic to improve state management and ensure proper session handling.

src/components/chat/ChatMessageList.tsx

@@ -21,7 +21,7 @@ function ChatMessageList({ messages, loading, showWelcomeState }: ChatMessageLis
   }, [messages]);
 
   return (
-    <div className="flex min-h-0 flex-1 flex-col overflow-hidden px-6 py-6">
+    <div className="flex min-h-0 flex-1 flex-col overflow-hidden p-6">
       <div ref={containerRef} className="flex min-h-0 flex-1 flex-col gap-4 overflow-y-auto pr-1">
         {loading ? (
           <div className="rounded-[18px] border border-dashed border-[#BEDBFF] bg-[#EFF6FF] px-4 py-3 text-sm text-[#525866] dark:border-[#2a2a2d] dark:bg-[#1f1f22] dark:text-gray-400">