Astra's review of #357. Every place that builds a strategy's folder now goes
through strategyFolderPath, including image cleanup, strategy delete and
export, which delete or read whole folders. A move to the cloud stops, and
keeps the original, when a picture's name is refused, instead of finishing
without it. A cloud image from before extensions were recorded keeps its
bare-id file name, as the server allows. A zip .ica only puts image files
in the images folder.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>