feat: add comment keyword blocking functionality

lib/pages/comic_details_page/comments_page.dart

@@ -1,5 +1,18 @@
 part of 'comic_page.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 CommentsPage extends StatefulWidget {
   const CommentsPage({
     super.key,
@@ -36,8 +49,9 @@ class _CommentsPageState extends State<CommentsPage> {
         _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;
       });
@@ -54,8 +68,9 @@ class _CommentsPageState extends State<CommentsPage> {
     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;

lib/pages/comic_details_page/comments_preview.dart

@@ -21,7 +21,7 @@ class _CommentsPartState extends State<_CommentsPart> {
 
   @override
   void initState() {
-    comments = widget.comments;
+    comments = widget.comments.where((c) => !_shouldBlockComment(c)).toList();
     super.initState();
   }