Add http caching for the new columns/edit card resource

app/controllers/cards/columns_controller.rb

@@ -1,5 +1,8 @@
 class Cards::ColumnsController < ApplicationController
   def edit
     @card = Current.user.accessible_cards.find(params[:card_id])
+    @columns = @card.collection.columns
+
+    fresh_when etag: [ @card, @columns ]
   end
 end

app/views/cards/columns/edit.html.erb

@@ -14,7 +14,7 @@
         aria: { checked: @card.awaiting_triage? },
         form_class: "flex align-center gap-half" %>
 
-    <% @card.collection.columns.each do |column| %>
+    <% @columns.each do |column| %>
       <%= button_to_set_column @card, column %>
     <% end %>