feat: implement comment blocking based on user-defined keywords

lib/pages/reader/chapter_comments.dart

@@ -1,5 +1,18 @@
 part of 'reader.dart';
 
+bool _shouldBlockComment(Comment comment) {
+  var blockedWords = appdata.settings["blockedCommentWords"] as List;
+  if (blockedWords.isEmpty) return false;
+  
+  var content = comment.content.toLowerCase();
+  for (var word in blockedWords) {
+    if (content.contains(word.toString().toLowerCase())) {
+      return true;
+    }
+  }
+  return false;
+}
+
 class ChapterCommentsPage extends StatefulWidget {
   const ChapterCommentsPage({
     super.key,
@@ -44,8 +57,9 @@ class _ChapterCommentsPageState extends State<ChapterCommentsPage> {
         _loading = false;
       });
     } else if (mounted) {
+      var filteredComments = res.data.where((c) => !_shouldBlockComment(c)).toList();
       setState(() {
-        _comments = res.data;
+        _comments = filteredComments;
         _loading = false;
         maxPage = res.subData;
       });
@@ -62,8 +76,9 @@ class _ChapterCommentsPageState extends State<ChapterCommentsPage> {
     if (res.error) {
       context.showMessage(message: res.errorMessage ?? "Unknown Error");
     } else {
+      var filteredComments = res.data.where((c) => !_shouldBlockComment(c)).toList();
       setState(() {
-        _comments!.addAll(res.data);
+        _comments!.addAll(filteredComments);
         _page++;
         if (maxPage == null && res.data.isEmpty) {
           maxPage = _page;