fix(frontend): rehydrate 根节点兼容 Element 无 getElementById

评论排序/点赞在 AJAX rehydrate 时 root 为 Element，调用 getElementById 抛 TypeError；改为 Document/Element 安全查找，并补上评论排序委托点击。

assets/js/core/comments.js

@@ -555,18 +555,33 @@
   }
 
   /* ====== 评论排序（最新 / 最早） ====== */
+  /**
+   * Locate #id within a rehydrate root.
+   * Document has getElementById; Element roots (AJAX panels) only have querySelector.
+   */
+  function findInScope(scope, id) {
+    scope = scope || document;
+    if (!scope) return null;
+    if (scope.nodeType === 9) {
+      return scope.getElementById(id);
+    }
+    if (scope.nodeType === 1) {
+      if (scope.id === id) return scope;
+      return typeof scope.querySelector === "function"
+        ? scope.querySelector("#" + id)
+        : null;
+    }
+    return null;
+  }
+
   function initCommentOrder(root) {
     var scope = root || document;
-    var commentsArea = scope.getElementById("comments");
+    var commentsArea = findInScope(scope, "comments");
     if (!commentsArea) return;
+    // Event delegation survives filter HTML replacement after AJAX rehydrate.
     if (commentsArea.dataset.orderInit === "1") return;
     commentsArea.dataset.orderInit = "1";
 
-    function getPaginationEl(root) {
-      if (!root) return null;
-      return root.querySelector(".aksrt-comment-pagination, .comment-navigation");
-    }
-
     function renderLoadingState() {
       var listContainer = commentsArea.querySelector("#comment-list");
       if (!listContainer) return;
@@ -625,6 +640,25 @@
           window.location.href = url.toString();
         });
     }
+
+    commentsArea.addEventListener("click", function (e) {
+      var target = e.target;
+      if (!target || typeof target.closest !== "function") return;
+
+      // 「只看作者」同时带 comment-orderby，需优先于排序按钮判断
+      var authorBtn = target.closest(".comment-author-filter");
+      if (authorBtn && commentsArea.contains(authorBtn)) {
+        e.preventDefault();
+        applyAuthorFilter(authorBtn.getAttribute("data-author-only") || "0");
+        return;
+      }
+
+      var orderBtn = target.closest(".comment-orderby[data-order]");
+      if (orderBtn && commentsArea.contains(orderBtn)) {
+        e.preventDefault();
+        applyCommentOrder(orderBtn.getAttribute("data-order") || "newest");
+      }
+    });
   }
 
   window.AksrtFrontend.register("aksrt-comment-system", function () { initCommentSystem(); });