compute_fov() was iterating through the entire grid to build a Python
list of visible cells, causing O(grid_size) performance instead of
O(radius²). On a 1000×1000 grid this was 15.76ms vs 0.48ms.
The fix returns None instead - users should use is_in_fov() to query
visibility, which is the pattern already used by existing code.
Performance: 33x speedup (15.76ms → 0.48ms on 1M cell grid)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
