fix(production-readiness): audit fixes — duplicate useState + route mismatch + stale @reserved

- ChatArea.tsx: remove duplicate useState(searchOpen) declaration on line 70
- scheduled_task/mod.rs: fix route from /api/scheduler/tasks to /api/v1/scheduler/tasks
  (matches admin-v2 service baseURL pattern and all other modules)
- scheduled_task/handlers.rs: remove @reserved annotations (now has Admin V2 frontend)
- scheduled_task/handlers.rs: update doc comments with correct /api/v1/ paths

desktop/src/components/ChatArea.tsx

@@ -67,7 +67,7 @@ export function ChatArea() {
 
   const [input, setInput] = useState('');
   const [pendingFiles, setPendingFiles] = useState<File[]>([]);
-  const [searchOpen, setSearchOpen] = useState(false);  const [searchOpen, setSearchOpen] = useState(false);
+  const [searchOpen, setSearchOpen] = useState(false);
   const scrollRef = useRef<HTMLDivElement>(null);
   const textareaRef = useRef<HTMLTextAreaElement>(null);
   const messageRefs = useRef<Map<string, HTMLDivElement>>(new Map());