refactor: simplify exponent parity responsibility in modularBinaryExp… - #64

Description
Refactored exponent parity evaluation in modularBinaryExponentiation (Maths/ModularBinaryExponentiationRecursive.js) into an explicit predicate helper to improve code clarity while preserving exact algorithm behavior.

Related Issue
Fixes: #26

Type of Change

• Bug Fix
• New Feature
• UI/UX Improvement
• Performance Improvement
• Tests
• Documentation
• Refactoring / Maintenance
• CI/CD

Changes Made

• Extracted isOddExponent predicate in Maths/ModularBinaryExponentiationRecursive.js to make the recursive branching step explicitly named and readable.
• Tested smallest valid input (base=2, exponent=0, mod=5 -> 1) and ordinary input (base=2, exponent=10, mod=1000 -> 24), referencing precondition source line 9.
• Added equivalence tests in Maths/test/ModularBinaryExponentiationRecursive.test.js across odd/even exponent cases.
• Created work/R50-T026/check.py to non-interactively run tests and log fixture results and versions.

Screenshots / Recordings
N/A

Testing

• Executed python3 work/R50-T026/check.py locally.
• Verified test suite passes for Maths/test/ModularBinaryExponentiationRecursive.test.js.

Checklist

• I have tested my changes locally.
• I have added or updated tests, if needed.
• I have updated documentation, if needed.
• I have followed the project's coding guidelines.
• I have run the relevant tests and checks.
• I have addressed previous review feedback, if applicable.

Additional Notes
N/A