feat(creator-studio): centered paper layout and scheduled publishing

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

assets/admin/src/schema/sections/post-list/submit.js

@@ -10,14 +10,14 @@ export const submitSchema = {
     post_article_custom_filter_s: true,
     post_article_tag: true,
     post_article_user: 1,
-    post_article_title_strlen_limit: { min: 5, max: 30 },
+    post_article_title_strlen_limit: { min: 5, max: 100 },
     post_article_pay_free_s: true,
     post_article_pay_price_limit: { price: { min: 0, max: 99999 }, points: { min: 0, max: 0 } },
     post_article_pay_vip_price_s: true,
     post_article_pay_vip_1_discount: 100,
     post_article_pay_vip_2_discount: 100,
-    post_t_placeholder: '请输入标题',
-    post_c_placeholder: '请输入内容',
+    post_t_placeholder: '请输入标题（最多 100 个字）',
+    post_c_placeholder: '请输入正文',
   },
   groups: [
     {
@@ -44,7 +44,7 @@ export const submitSchema = {
         },
         { key: 'post_article_tag', label: '允许插入标签', type: 'switch', default: true, dependsOn: { key: 'post_article_s', value: true }, description: '前台投稿时候允许设置文章标签' },
         { key: 'post_article_user', label: '免登陆投稿发布用户', type: 'user_select', default: 1, dependsOn: { key: 'post_article_s', value: true }, description: '当选择投稿权限为无需登录就能投稿时，投稿文章的用户' },
-        { key: 'post_article_title_strlen_limit', label: '标题字数限制', type: 'between_number', default: { min: 5, max: 30 }, unit: '字', description: '限制标题字数可有效的防止灌水等无意义内容（英文字符按0.5个字计算）' },
+        { key: 'post_article_title_strlen_limit', label: '标题字数限制', type: 'between_number', default: { min: 5, max: 100 }, unit: '字', description: '限制标题字数可有效的防止灌水等无意义内容（英文字符按0.5个字计算）' },
         { key: 'post_article_pay_free_s', label: '允许设置为免费资源', type: 'switch', default: true, dependsOn: { key: 'post_article_s', value: true }, description: '付费内容金额允许设置为 0' },
         {
           key: 'post_article_pay_price_limit',