🧪 Add tests for Mat4::perspective

[google-labs-jules]

🎯 What: The testing gap addressed is the lack of test coverage for the Mat4::perspective function in the soft_render library.
📊 Coverage: Test coverage includes standard matrices verification against mathematically derived formulas, and testing projection limits (near plane, far plane, right corner, top corner limits on NDC maps: near z=-1, far z=1).
✨ Result: A robust testing baseline for Mat4 perspective mappings, which should assist future refactoring and optimization tasks.

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PR created automatically by Jules for task 6300824455588772539 started by @EricBorges2019

[google-labs-jules]

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