Artemis: Optimize numerical calculations and fix edge cases

[mike-turintech]

This PR includes several optimizations and bug fixes for numerical calculations:

• Improved sumRange() performance by replacing array-based calculation with direct mathematical formula, reducing complexity from O(n) to O(1)
• Fixed maxArray() to correctly handle negative numbers by initializing max value to Integer.MIN_VALUE
• Optimized sumModulus() by replacing Vector/stream implementation with arithmetic progression formula, eliminating memory overhead and improving performance

These changes result in better performance, correct handling of edge cases, and more maintainable code.