feat(materials): free rotate session overlays and show save progress

Match NPC drag-to-rotate on the material frame during playback, and change the add/edit Save button to Saving… while import runs.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/shared/PresentationView.tsx

@@ -167,7 +167,6 @@ export function PresentationView({
       {activeMaterial ? (
         <MaterialOverlay
           assetId={activeMaterial.assetId}
-          rotationDeg={activeMaterial.rotationDeg ?? 0}
           layout={materialsOverlay?.layout ?? DEFAULT_MATERIALS_OVERLAY_LAYOUT}
         />
       ) : null}