Add custom mathematical functions and call counter

[kdraltntas]

Defines custom_power lambda and custom_equation function for mathematical calculations. Implements fn_w_counter to track function call counts and caller information.

Describe your changes

Checklist

• I have read the [CONTRIBUTING]
• I have performed a self-review of my own code
• I have run the code locally and it works as expected
• I have commented my code, particularly in hard-to-understand areas

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