- Implemented StageSurfaceColorDialog for custom color selection with live preview.
- Created StageBackgroundGround class for non-walkable scenery behind the set.
- Introduced StageRectSurface for shared rectangular geometry and tint preview.
- Added StageSurfacePreview for rendering surface previews.
- Developed comprehensive tests for surface color selection, rendering, and serialization.
- Added UI/UX specification for prop roles and set down mechanics in phase 17a.
- Created `PropStageRoles` script to manage normalized behavior for props, including depth, motion, and collision settings.
- Introduced `StagePhysicsPolicy` for shared physics configurations related to props and actors.
- Developed comprehensive tests for prop roles, including default settings, legacy migration, serialization, and runtime behavior.
- Ensured proper handling of set down actions, including clearance and orientation preservation.
ryan