🧪 Add test for quadratic_weighted_roll distribution

[perim]

🎯 What: The quadratic_weighted_roll function lacked a unit test verifying its underlying distribution.
📊 Coverage: A test case test_quadratic_weighted_roll_distribution has been introduced mimicking test_pow2_weighted_roll_distribution. It tests high = 4 using 1,000,000 rolls to statistically verify the expected quadratic distribution.
✨ Result: Test coverage for quadratic_weighted_roll probabilities and boundary outcomes ensures robust determinism. Flakiness is negated using a generous standard deviation bound.

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PR created automatically by Jules for task 12287809464926516590 started by @perim

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