🧪 Add missing unit tests for Ray2D geometry struct

[johnstrand]

🎯 What: Added a unit test suite for the Ray2D geometry struct (tests/GameUtils.Tests/Geometry/Ray2DTests.cs).
📊 Coverage: Covered constructor direction normalization, zero-vector validation, At point calculation, and Intersects overloads for Line, Circle, and AABB including hit/miss outcomes, behind-ray cases, and origin inside shape.
✨ Result: Resolves missing unit tests for Ray2D, increasing codebase reliability and test coverage.

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PR created automatically by Jules for task 17999853574240632571 started by @johnstrand

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