📝 docs(shadcn-manage-page): update modal form documentation

- add guidance for separating create and edit forms
- provide example code for independent rendering of create/edit forms
- remove recommendation for ternary operator inside Form component props

.roo/commands/shadcn-manage-page.md

@@ -199,6 +199,20 @@ const updateForm = useForm<UpdateRequest>({
 ```
 
 ### 2. 模态框表单（创建/编辑分离模式）
+
+将 创建/编辑表单分离
+不要 <Form {...(isCreateForm ? createForm : updateForm)}></Form>
+要     
+{isCreateForm ? (
+  // 创建表单（独立渲染）
+  <Form {...createForm}>
+  </Form>
+) : (
+  // 编辑表单（独立渲染）
+  <Form {...updateForm}>
+  </Form>
+)}
+
 ```tsx
 <Dialog open={isModalOpen} onOpenChange={setIsModalOpen}>
   <DialogContent className="sm:max-w-[500px] max-h-[90vh] overflow-y-auto">