feat: 插件适配页面与系统完善（v0.1.0）

- 修复 /categories、/tags 因变量为 List 误用 .items 导致的 500
- 新增 layout.html 布局契约，消除插件页面 fallback 警告
- 适配 plugin-moments / plugin-photos / plugin-links（含友链申请表单与 RSS 订阅页）
- 适配 halo-weread-plugin（书架页）、留言板单页模板
- 适配 plugin-extra-api 的代码高亮与暗色样式
- 修复暗黑模式评论区不可见（补充 color-scheme 与兜底样式）
- 更新元数据：作者暖心向阳335、版本 0.1.0、requires >=2.26.0

src/categories.html

@@ -1,22 +1,28 @@
-<include src="layout.html">
+<include src="partials/layout.html">
   <template name="head">
-    <title th:text="|Categories - ${site.title}|">Categories</title>
+    <title th:text="|#{categories.title} - ${site.title}|">Categories</title>
+    <th:block
+      th:with="seoTitle=#{categories.title}, seoUrl=${site.url + site.routes.categoriesUri}, seoDesc=null, seoImage=${site.logo}, seoType='website'"
+    >
+      <include src="seo.html"></include>
+    </th:block>
   </template>
 
-  <h1>Categories</h1>
-  <ul class="category-list">
-    <li th:each="cat : ${categories.items}">
-      <a
-        th:href="@{${cat.status.permalink}}"
-        th:text="|${cat.spec.displayName} (${cat.postCount})|"
-        class="category"
-      ></a>
-    </li>
-  </ul>
+  <div class="container">
+    <div class="category-header">
+      <h1 class="category-title" th:text="#{categories.title}">
+        Categories
+      </h1>
+    </div>
 
-  <nav class="pagination" th:if="${categories.hasPrevious() || categories.hasNext()}">
-    <a th:if="${categories.hasPrevious()}" th:href="@{${categories.prevUrl}}">Previous</a>
-    <span th:text="|${categories.page} / ${categories.totalPages}|"></span>
-    <a th:if="${categories.hasNext()}" th:href="@{${categories.nextUrl}}">Next</a>
-  </nav>
+    <div class="category-list" th:if="${not #lists.isEmpty(categories)}">
+      <th:block
+        th:replace="~{modules/category-tree :: category-tree(cats=${categories})}"
+      ></th:block>
+    </div>
+
+    <div class="no-results" th:if="${#lists.isEmpty(categories)}">
+      <p th:text="#{list.empty}">Nothing found here.</p>
+    </div>
+  </div>
 </include>