## Vector Terrain System

Now that stickmen can be spawned, we need to implement a world for the character.
We want the world to be based on vector graphics so that camera zooming and panning as smooth and crisp.
According to ROADMAP.md, we want to start with vector terrains.

The following phases need work:

### Phase 1. Reusable TerrainBlock Component (StaticBody2D)

- Node Hierarchy: A root StaticBody2D with three direct children: Polygon2D for interior fill, Line2D for crisp vector borders, and CollisionPolygon2D for physics boundaries.
- Property Exposure: An @tool script exposing exported properties for polygon_points (PackedVector2Array), fill_color, outline_color, and outline_width.
- Auto-Update Logic: A unified property setter that pushes vertex changes directly to Polygon2D and CollisionPolygon2D (configured with BUILD_SOLIDS), while automatically appending the first vertex to the end of Line2D to close the border loop with rounded line joints.

### Phase 2. PhysicsTestHarness Test Scene

- Scene Layout: A standalone test root containing a Camera2D, an environment container with flat ground, angled ramps, and stepped TerrainBlock instances, plus an instantiated MasterRig.
- Camera Verification: A simple input script on Camera2D that scales zoom levels between 0.25x and 3.0x on mouse wheel scroll to test resolution independence and vector outline thickness.

### Phase 3. TerrainUtils Geometry Engine

- Point Sanitization: A static utility class that processes raw input points by applying grid snapping, running Geometry2D.simplify_polyline() to remove redundant nodes, and enforcing clockwise vertex ordering via Geometry2D.is_polygon_clockwise() for solid collision detection.
- Factory Spawner: A helper function that takes user input vectors, processes them through the sanitization pipeline, creates a new TerrainBlock instance, applies the cleaned points, and adds it to the target container.