Explode Everything 1.2.0

This update fixes the animation and callout issues reported by customers.

- New: Reassemble at End (on by default). After the last step the whole exploded view holds with every label, then the labels fade out and all parts move back together.

- New: Visible Surface anchor (now the default). Every marker sits on a point of its own part that the camera really sees, never in a hole, in empty space or on a part in front.

- Fixed: labels pointed at the wrong component when a whole imported model was selected. Group empties no longer get their own label; an empty selected on its own explodes its sub-assembly as one part.

- Fixed: rebuilding while the timeline showed an exploded frame gave a different, wrong explode every time.

- Fixed: old labels stayed behind and never disappeared after rebuilding with fewer parts, deleting a part or using Split into Parts.

- Fixed: parts parented with Ctrl+P to a rotated or scaled parent moved the wrong distance.

- Fixed: Blender froze for minutes when arranging labels on models with many parts (now seconds).

- Fixed: Build Explainer Animation no longer deletes your own callouts when Labels is off.

- New: a warning when parts end up outside the camera view, so their labels are not silently hidden.

- Changed: Clear Animation also removes the labels the animation created.

- Changed: Fit Scene Frame Range now matches the animation length exactly.