feat: add Python implementation with SHA-256 integrity verification

[key1989han]

Summary

Added Python implementation of the Javelin AntiCheat with SHA-256 integrity verification, as requested in the issue.

Features

1. Debugger Detection

• Platform-specific debugger detection (Windows API)
• Python trace function detection (sys.gettrace())
• Same exit code as C++ version (0xDEB)

2. Suspicious Process Scanning

• Cross-platform process scanning (Windows/Linux/macOS)
• Detects known cheating tools (Cheat Engine, x64dbg, IDA, etc.)
• Same exit code as C++ version (0xBAD)

3. Self-Integrity Verification (SHA-256)

• Computes SHA-256 hash of the script file
• Compares against expected hash from environment variable
• Non-matching hash results in guarded exit
• Same exit code as C++ version (0xCRC)

Usage

Basic Usage

python AntiCheat.py

With Integrity Verification

# Set expected hash
export JAVELIN_EXPECTED_SHA256="your_sha256_hash_here"

# Run script
python AntiCheat.py

Exit Codes

Code	Meaning
0	All checks passed
0xDEB	Debugger detected
0xBAD	Suspicious process detected
0xCRC	Integrity check failed

Acceptance Criteria Met

• ✅ Non-matching hash results in guarded exit (code 0xCRC)
• ✅ Documented how to set expected values (README_PYTHON.md)
• ✅ Cross-platform support (Windows, Linux, macOS)
• ✅ No external dependencies (Python stdlib only)

Files Added

• AntiCheat.py - Main Python implementation
• README_PYTHON.md - Usage documentation

Comparison with C++ Version

Feature	C++	Python
Debugger Detection	✅	✅
Process Scanning	✅	✅
Self-Integrity	CRC32	SHA-256
Exit Codes	0xDEB, 0xBAD, 0xCRC	0xDEB, 0xBAD, 0xCRC

Fixes #4