Fixed issue where affected zones contained too many zones on simple changes. The bug occurred in two places:
1. **GridFiller*WithAffected methods**: Now properly track zones that were added, removed, or had their rectangles modified using SymmetricExceptWith and comparing rectangle geometries. This prevents returning all zones when only a few actually changed.
2. **IncrementalUpdateGraph**: Was not clearing adjacencies FROM non-affected zones TO affected zones, causing stale adjacencies to persist. Now removes all references from other zones to affected zones before recalculating, ensuring a clean slate for adjacency recalculation.
Testing with ValidateIncrementalUpdates confirms that incremental updates now match full rebuilds exactly.
Co-authored-by: Copilot <[email protected]>
Stone_Red
