- EditorActorLayer now tracks previews on map with a SpatiallyPartitioned instead of a Dictionary. This allows the copy-paste logic to call an efficient PreviewsInCellRegion method, instead of asking for previews cell-by-cell.
- EditorActorPreview subscribes to the CellEntryChanged methods on the map. Previously the preview was refreshed regardless of which cell changed. Now the preview only regenerates if the preview's footprint has been affected.
If you edit an actor name, then delete the actor - it fails to be removed from the map in the editor. This is because the actor previews are keyed by ID. Editing their name edits their ID and breaks the stability of their hash code. This unstable hash code means the preview will now fail to be removed from collections, even though it's the "same" object.
Fix this by making the ID immutable to ensure hash stability - this means that a preview can be added and removed from collections successfully. Now when we edit the ID in the UI, we can't update the ID in place on the preview. Instead we must generate a new preview with the correct ID and swap it with the preview currently in use.
This allows TraitInfos to act when the actor preview is placed
in the editor, returning arbitrary data which the editor stores
and gives back if the preview is removed.
This avoids the allocations caused by LINQ when using traits.FirstOrDefault(Exts.IsTraitEnabled). This is important in FrozenActorLayer.RefreshState which is called very often. We apply the new helper method to all areas using the old pattern. An overload that takes an array allows arrays to be enumerated without causing allocations.
