fix(homepage): align shell with zibll and restore post stream

Move header-slider outside main, render fluid zones once, default the
latest stream to plain posts by date, and cut dual-render/perf waste so
published posts and hero/banner structure match the zibll contract.

assets/admin/src/schema/sections/page-display/index.js

@@ -931,13 +931,13 @@ export const pageDisplaySchemas = {
     icon: 'fas fa-home',
     description: '配置首页内容模型、主列表、分类 Tab、卡片样式与首页交互。实际编辑界面在 HomepageSettings.vue（customPage），此处补齐 page_display 的 schema 契约。',
     defaults: {
-      homepage_content_model: 'mixed',
+      homepage_content_model: 'post',
       homepage_tabs: [],
       homepage_card_style: 'default',
-      homepage_multi_thumb_enabled: true,
+      homepage_multi_thumb_enabled: false,
       homepage_multi_thumb_min_images: 3,
       homepage_sidebar_mini_enabled: true,
-      homepage_default_sort: 'modified',
+      homepage_default_sort: 'date',
       homepage_default_view: 'list',
       homepage_sort_ajax_enabled: true,
       homepage_sticky_tabs_enabled: true,
@@ -961,7 +961,7 @@ export const pageDisplaySchemas = {
             key: 'homepage_content_model',
             label: '首页内容模型',
             type: 'radio',
-            default: 'mixed',
+            default: 'post',
             options: [
               { label: '混合模式', value: 'mixed' },
               { label: '纯文章', value: 'post' },
@@ -977,7 +977,7 @@ export const pageDisplaySchemas = {
         fields: [
           { key: 'home_posts_list_s', label: '启用主列表', type: 'switch', default: true },
           { key: 'index_list_title', label: '区块标题', type: 'input', default: '最新发布', dependsOn: { key: 'home_posts_list_s', value: true } },
-          { key: 'home_list1_orderby_option.orderby', label: '默认排序', type: 'select', default: 'modified', dependsOn: { key: 'home_posts_list_s', value: true }, options: sortOptions },
+          { key: 'home_list1_orderby_option.orderby', label: '默认排序', type: 'select', default: 'date', dependsOn: { key: 'home_posts_list_s', value: true }, options: sortOptions },
           { key: 'home_list1_orderby_s', label: '启用排序栏', type: 'switch', default: true, dependsOn: { key: 'home_posts_list_s', value: true } },
           { key: 'home_list_sort_dropdown', label: '排序栏下拉模式', type: 'switch', default: false, dependsOn: { key: 'home_list1_orderby_s', value: true } },
           { key: 'home_list1_orderby_option', label: '可用排序选项', type: 'checkbox', default: ['modified', 'date', 'views', 'likes', 'comments'], dependsOn: { key: 'home_list1_orderby_s', value: true }, options: sortOptions },