feat: add baseline anti-cheat monitor

[haradahinata]

/claim #2
/claim #4

Summary

• makes the native AntiCheat.cpp build cleanly with MSVC while preserving Windows debugger and suspicious-process checks
• adds a dependency-light anti_cheat.py monitor for Python clients with debugger detection, suspicious process detection, and opt-in SHA-256 script integrity verification
• documents the C++ CRC32 and Python SHA-256 integrity setup flows
• adds focused Python regression tests for parsing, suspicious-process matching, integrity success/failure, and guarded exit codes

Verification

• py -m unittest discover -s tests -> 11 tests passed
• py -m py_compile anti_cheat.py tests\test_anti_cheat.py
• cl /std:c++17 /EHsc AntiCheat.cpp /Fe:AntiCheat.exe
• AntiCheat.exe -> [Javelin AntiCheat] All clear. Continue.
• git diff --check

This was AI-assisted and manually reviewed/tested before submission.

[haradahinata]

Demo asset for the bounty guidelines: https://github.com/haradahinata/py-workedtask/releases/download/pr-30-demo-20260518/py-workedtask-pr30-demo.gif

It shows the Python test run, MSVC C++ build, clean runtime path, and guarded integrity-failure path. The underlying validation commands are listed in the PR body.