Fix: Hide private charts in variants

backend/app/models/chart.rb

@@ -14,7 +14,7 @@ class Chart < ApplicationRecord
                   }
 
   has_many :file_resources, dependent: :destroy
-  has_many :variants,
+  has_many :_variants,
            class_name: "Chart",
            foreign_key: "variant_id",
            dependent: :nullify,
@@ -23,7 +23,7 @@ class Chart < ApplicationRecord
              class_name: "Chart",
              optional: true,
              foreign_key: "variant_id",
-             inverse_of: :variants
+             inverse_of: :_variants
   has_many :likes, dependent: :destroy
   has_many :tags, dependent: :destroy
   enum chart_type: { sus: 0, mmws: 1, chs: 2, usc: 3 }
@@ -50,6 +50,10 @@ def resources
       background_v1: base.find(&:background_v1?)
     }
   end
+
+  def variants(include_private: false)
+    _variants.filter(&visibility_public?)
+  end
 
   def to_frontend(user: nil, with_resources: true, with_variants: true)
     resources = with_resources ? self.resources : {}