🧪 Add unit tests for Quad geometry struct

[johnstrand]

🎯 What: Added unit tests for the Quad geometry struct to fill the missing test coverage gap.

📊 Coverage:

• Constructors: Tested initialization via Vector2 corner points, float corner points, float position/size, and Vector2 position/size.
• Indexer: Tested valid index access (0 through 3) and verified ArgumentOutOfRangeException is thrown for invalid indices (-1 and 4).
• Intersection: Tested line intersection returning true with the expected nearest point, and line non-intersection returning false with null.

✨ Result: Improved test suite coverage and reliability for geometry types.

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PR created automatically by Jules for task 12496032689898804617 started by @johnstrand

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