Refresh models from all working connections (progressive update - adds/removes missing models). Only processes connections where is_working = true.
When refreshing: - Only processes connections where connection.is_working = true - Skips connections that are not working (don't attempt to fetch models from them) - Compares fetched models with existing models in the store - Adds new models that don't exist - Removes models from connections that are no longer working or available - Don't clear and reload everything