Artifact (saved results) improvements

Each save is now kept as a new result

When you save a result as an artifact, the title now includes the time it was saved, so each save is kept as its own separate entry (embedded mode). Previous saves are no longer overwritten, so you can view and compare results from multiple runs side by side.

Buttons now behave consistently, making their state clear

The buttons for downloading and saving results now follow the same "preparing → ready" flow. They show a spinner while preparing and become active once ready, so every button behaves consistently and its state is clear at a glance.

Loading display improvements

Progress is now shown while overlay models load

When loading a model displayed on top of another (an overlay model), the actual progress is now shown. You can see that loading is underway and get a sense of how close it is to finishing.