Don't save models to disk when refreshing.

Fixes issues in production with read only filesystems.

Author: crmne

lib/ruby_llm/models.rb

@@ -40,7 +40,6 @@ def refresh! # rubocop:disable Metrics/AbcSize,Metrics/CyclomaticComplexity,Metr
 
         all = (preserved + configured.flat_map(&:list_models)).sort_by(&:id)
         @instance = new(all)
-        @instance.save_models
         @instance
       end