ColorLayer enhancements:
- fill_rect(x, y, w, h, color): Fill rectangular region
- draw_fov(source, radius, fov, visible, discovered, unknown): One-time FOV draw
- apply_perspective(entity, visible, discovered, unknown): Bind layer to entity
- update_perspective(): Refresh layer from bound entity's gridstate
- clear_perspective(): Remove entity binding
New demo: tests/demo/perspective_patrol_demo.py
- Entity patrols around 10x10 central obstacle
- FOV layer shows visible/discovered/unknown states
- [R] to reset vision, [Space] to pause, [Q] to quit
- Demonstrates fog of war memory system
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
