Add post_hash_tags_max setting

app/models/admin/ng_word.rb

@@ -6,10 +6,23 @@ class Admin::NgWord
       ng_words.any? { |word| text.include?(word) }
     end
 
+    def hashtag_reject?(hashtag_count)
+      post_hash_tags_max.positive? && post_hash_tags_max < hashtag_count
+    end
+
+    def hashtag_reject_with_extractor?(text)
+      hashtag_reject?(Extractor.extract_hashtags(text)&.size || 0)
+    end
+
     private
 
     def ng_words
       Setting.ng_words
     end
+
+    def post_hash_tags_max
+      value = Setting.post_hash_tags_max
+      value.is_a?(Integer) && value.positive? ? value : 0
+    end
   end
 end

app/models/form/admin_settings.rb

@@ -37,12 +37,14 @@ class Form::AdminSettings
     ng_words
     enable_block_emoji_reaction_settings
     hide_local_users_for_anonymous
+    post_hash_tags_max
   ).freeze
 
   INTEGER_KEYS = %i(
     media_cache_retention_period
     content_cache_retention_period
     backups_retention_period
+    post_hash_tags_max
   ).freeze
 
   BOOLEAN_KEYS = %i(