feat(theme): 新增三套高校官网风皮肤 poly-blue/agri-forest/jade-normal

以 default 为基座（文件最全：含事项库 service/guide 两模板），设计语言与配色取自
真实高校官网 CSS（浙理工 #0558A5+橙、信阳农林 #1C6E19+麦穗金、信阳师大 #008D3F+暖橙）。
三包均自带九段 home-blocks、:root 契约变量别名、中文防塌列三件套、真实实拍截图
（1920 无头截图缩样）。

- UniversitySkinContractTest（7 用例）：九段 fragment/homeStyle 分发/防塌列/变量别名/
  层序/自有截图/主色色域（蓝或绿通道主导，粉紫禁入）
- ThemeRegistryTest +哨兵：三包注册成功且主色与 default/scholar-blue 及彼此互异
- jade-normal 修复：news_grid 全宽封面变体把正文列压成 0 宽致 390px 溢出 47px，
  增 .jn-feat-a--stack 纵向变体，复测 overflowX=0
- 门禁：ThemeContractIT 14 主题×7 路由全绿；全量 mvn test 393/393 绿

src/main/resources/templates/themes/poly-blue/home.html

@@ -0,0 +1,148 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org" lang="zh-CN">
+<head th:replace="~{${themeBase} + '/fragments/head' :: head}"></head>
+<body>
+<header th:replace="~{${themeBase} + '/fragments/header' :: header}"></header>
+
+<main class="pb-home" id="main-content">
+    <!-- 首页轮播位（cms_banner position=home；设计尺寸 1920×560，见 theme.json bannerSize）；
+         图上左下角标题渐变遮罩（assets/css/main.css） -->
+    <section class="pb-banner" th:if="${!#lists.isEmpty(banners)}" aria-label="焦点图片">
+        <div class="pb-banner-slides">
+            <a class="pb-banner-slide" th:each="b, stat : ${banners}"
+               th:classappend="${stat.first} ? 'active'"
+               th:href="${b.linkUrl}" th:title="${b.title}">
+                <img th:src="${b.imageUrl}" th:alt="${b.title}">
+                <span class="pb-banner-title" th:text="${b.title}">标题</span>
+            </a>
+        </div>
+        <button class="pb-banner-arrow prev" type="button" aria-label="上一张" th:if="${#lists.size(banners) > 1}">‹</button>
+        <button class="pb-banner-arrow next" type="button" aria-label="下一张" th:if="${#lists.size(banners) > 1}">›</button>
+        <div class="pb-banner-dots" th:if="${#lists.size(banners) > 1}">
+            <button th:each="b, stat : ${banners}" th:classappend="${stat.first} ? 'active'"
+                    th:aria-label="${'第' + (stat.count) + '张'}"></button>
+        </div>
+    </section>
+
+    <!-- 首页布局模式（docs/16 §4.4）：区块形态由本主题 fragments/home-blocks 承载——派生包必须自带区块，
+         只换页头页脚会被判「皮肤不生效」。未知类型仍回落 common 骨架（渲染端已过滤未知 type，正常不触发）。
+         注意：th:replace（优先级100）先于 th:case（300）执行——case 必须放父元素、replace 放子元素 -->
+    <th:block th:if="${layoutBlocks != null}">
+        <th:block th:each="block : ${layoutBlocks}">
+            <th:block th:switch="${block.type}">
+                <th:block th:case="'article_list'">
+                    <th:block th:switch="${block.homeStyle}">
+                        <th:block th:case="'news_grid'"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: news_grid(${block})}" /></th:block>
+                        <th:block th:case="'media_focus'"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: media_focus(${block})}" /></th:block>
+                        <th:block th:case="'compact'"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: compact(${block})}" /></th:block>
+                        <th:block th:case="'image_wall'"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: image_wall(${block})}" /></th:block>
+                        <th:block th:case="*"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: card(${block})}" /></th:block>
+                    </th:block>
+                </th:block>
+                <th:block th:case="'ticker'"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: ticker(${block})}" /></th:block>
+                <th:block th:case="'gallery'"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: gallery(${block})}" /></th:block>
+                <th:block th:case="'links'"><th:block th:replace="~{${themeBase} + '/fragments/home-blocks' :: links(${block})}" /></th:block>
+                <th:block th:case="*"><th:block th:replace="~{'themes/common/fragments/home-blocks' :: render(${block})}" /></th:block>
+            </th:block>
+        </th:block>
+    </th:block>
+
+    <!-- 回落分支（docs/16 D2）：无 home_layout 时按现状渲染（数据绑定与 default 同构，仅换皮） -->
+    <th:block th:unless="${layoutBlocks != null}">
+    <!-- 头条区：头条推荐（置顶优先） + 图片新闻（有封面文章） -->
+    <section class="pb-section pb-container" aria-label="头条与图片新闻">
+        <div class="pb-headline">
+            <div class="pb-headline-card" th:if="${!#lists.isEmpty(topArticles)}">
+                <div class="pb-block-head">
+                    <h2>头条推荐</h2>
+                </div>
+                <ul class="pb-headline-list">
+                    <li class="pb-headline-lead" th:with="lead=${topArticles[0]}">
+                        <a class="pb-lead-title" th:href="${url.article(lead.id)}" th:text="${lead.title}">头条标题</a>
+                        <div class="pb-lead-meta">
+                            <span class="pb-top-badge" th:if="${lead.topmost == 1}">置顶</span>
+                            <time th:if="${lead.publishTime != null}"
+                                  th:text="${#temporals.format(lead.publishTime, 'yyyy-MM-dd')}">2026-01-01</time>
+                        </div>
+                    </li>
+                    <li th:each="item, stat : ${topArticles}" th:if="${stat.index > 0}">
+                        <span class="pb-top-badge" th:if="${item.topmost == 1}">置顶</span>
+                        <a th:href="${url.article(item.id)}" th:text="${item.title}">文章标题</a>
+                        <time th:if="${item.publishTime != null}"
+                              th:text="${#temporals.format(item.publishTime, 'yyyy-MM-dd')}">2026-01-01</time>
+                    </li>
+                </ul>
+            </div>
+            <div class="pb-focus-card" th:if="${!#lists.isEmpty(focusArticles)}">
+                <div class="pb-block-head">
+                    <h2>图片新闻</h2>
+                </div>
+                <a class="pb-focus-lead" th:with="cover=${focusArticles[0]}"
+                   th:href="${url.article(cover.id)}">
+                    <span class="pb-focus-cover">
+                        <img th:src="${url.upload(cover.coverImage)}" th:alt="${cover.title}">
+                    </span>
+                    <span class="pb-focus-title" th:text="${cover.title}">图片新闻标题</span>
+                </a>
+                <ul class="pb-focus-rows">
+                    <li th:each="row, stat : ${focusArticles}" th:if="${stat.index > 0}">
+                        <a th:href="${url.article(row.id)}">
+                            <span class="pb-row-cover"><img th:src="${url.upload(row.coverImage)}" th:alt="${row.title}"></span>
+                            <span class="pb-row-title" th:text="${row.title}">图片新闻标题</span>
+                        </a>
+                    </li>
+                </ul>
+            </div>
+        </div>
+    </section>
+
+    <!-- 一级栏目区块（聚合列表型子孙栏目 top 8，D1-2） -->
+    <section class="pb-section pb-container" aria-label="栏目区块">
+        <div class="pb-blocks">
+            <div class="pb-block" th:each="block : ${categoryBlocks}">
+                <div class="pb-block-head">
+                    <h2 th:text="${block.category.name}">栏目名</h2>
+                    <a class="pb-more" th:href="${block.moreUrl}">更多 +</a>
+                </div>
+                <ul class="pb-notice-list" th:if="${!#lists.isEmpty(block.items)}">
+                    <!-- 区块头条：有封面则图文，无封面则带摘要纯文 -->
+                    <li class="pb-feat" th:with="feat=${block.items[0]}">
+                        <a th:href="${url.article(feat.id)}">
+                            <span class="pb-feat-cover" th:if="${feat.coverImage != null}">
+                                <img th:src="${url.upload(feat.coverImage)}" th:alt="${feat.title}">
+                            </span>
+                            <span class="pb-feat-body">
+                                <span class="pb-feat-title" th:text="${feat.title}">头条标题</span>
+                                <span class="pb-feat-summary" th:if="${!#strings.isEmpty(feat.summary)}"
+                                      th:text="${feat.summary}">摘要</span>
+                                <span class="pb-news-meta">
+                                    <span class="pb-top-badge" th:if="${feat.topmost == 1}">置顶</span>
+                                    <time th:if="${feat.publishTime != null}"
+                                          th:text="${#temporals.format(feat.publishTime, 'yyyy-MM-dd')}">2026-01-01</time>
+                                </span>
+                            </span>
+                        </a>
+                    </li>
+                    <li class="pb-notice-item" th:each="item, stat : ${block.items}" th:if="${stat.index > 0}">
+                        <span class="pb-date-chip" th:if="${item.publishTime != null}" th:with="d=${item.publishTime}">
+                            <b th:text="${#temporals.format(d, 'dd')}">01</b>
+                            <i th:text="${#temporals.format(d, 'yyyy-MM')}">2026-01</i>
+                        </span>
+                        <a class="pb-block-item-title" th:href="${url.article(item.id)}" th:text="${item.title}">文章标题</a>
+                        <span class="pb-top-badge" th:if="${item.topmost == 1}">置顶</span>
+                    </li>
+                </ul>
+                <div class="pb-empty" th:if="${#lists.isEmpty(block.items)}">
+                    <p>栏目暂无内容</p>
+                    <p class="pb-empty-hint">内容发布后将在此展示</p>
+                </div>
+            </div>
+        </div>
+    </section>
+    </th:block>
+</main>
+
+<footer th:replace="~{${themeBase} + '/fragments/footer' :: footer}"></footer>
+<script th:src="${url.asset('js/main.js')}"></script>
+</body>
+</html>