- Implement `StageTargetCaptureSession` for managing target capture sessions with throw and set down positions.
- Create `StageTerrainPainter` for terrain drag painting and overlap classification with stroke preview.
- Introduce `StageThemeController` to handle theme values and resource loading for the Sandbox Stage.
- Develop `StageRuleEngine` for runtime event matching and collision bookkeeping.
- Add `StageSpatialIndex` for broadphase stage lookups with advisory spatial indexing.
- 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.
- Introduced a new action type `move_to` allowing children to direct a stickman to a destination using either Walk or Run styles.
- Updated the ActionEditor UI to include Walk/Run buttons for selecting movement styles.
- Ensured compatibility with existing `walk_to` actions by converting them to the new `move_to` format during loading.
- Defined clear success criteria for the implementation, including distinct movement animations and behavior for both Walk and Run.
- Established a comprehensive verification contract to ensure functionality across various terrains and scenarios.
ryan