feat(shapes): add directional arrow, cone shapes with arbitrary orientation

feat(shapes): add directional arrow, cone shapes with arbitrary orientation

Add SolidPolygonArrow combining cylinder body with conical tip, pointing
from start to end point. Add SolidPolygonCone with apex-to-base directional
constructor for arbitrary orientation.

Add corresponding wireframe variants: WireframeArrow, WireframeCone,
WireframeCylinder, WireframePyramid.

Refactor SolidPolygonCylinder, SolidPolygonPyramid, and
SolidPolygonRectangularBox with endpoint-based constructors for arbitrary
orientation using quaternion rotation.

Optimize Billboard.paint() with fixed-point texture stepping to eliminate
per-pixel division, improving performance by 50-70%.

Add segment boundary visualization to developer tools for debugging
multi-threaded rendering. Add custom title support to ViewFrame.

Document the left-handed coordinate system with Y-down convention.