⚡ Optimize AABB-Polygon intersection with early bounds rejection

[johnstrand]

💡 What:

• Implemented a fast early-out bounding box check for AABB.Intersects(Polygon2D) by evaluating the polygon's min/max bounds on the fly against the AABB's bounds.
• Fixed a bug where AABB.Intersects(Polygon2D) returned false if the AABB was completely inside the polygon (added a polygon.Contains(Center) check as a fallback).
• Added GameUtils.Benchmarks project to establish baseline measurements using BenchmarkDotNet.
• Added comprehensive unit tests in GameUtils.Tests.Geometry.AABBTests to verify all intersection edge cases.

🎯 Why:
The previous implementation iterated through all vertices and edges of a polygon regardless of how far apart the shapes were. By first calculating and checking against the polygon's bounding box, we drastically reduce the work required for shapes that don't intersect, solving the performance bottleneck on collision hot paths. The bug where a contained AABB did not register an intersection was also resolved to ensure mathematical correctness.

📊 Measured Improvement:
Using BenchmarkDotNet with 4 scenarios (Inside, Intersecting, Outside, ContainsAABB):

• Baseline IntersectsOutside: ~35.513 ns
• Optimized IntersectsOutside: ~11.654 ns
• Improvement: ~67% faster for completely non-intersecting shapes, which is by far the most common path in spatial queries. IntersectsIntersecting and IntersectsInside cases are slightly faster/comparable, as expected, but the overall speedup for collision rejection is immense.

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PR created automatically by Jules for task 5602852543587852411 started by @johnstrand

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