Rename to entropymon, restructure as PyPI package

- Renamed systats -> entropymon everywhere (code, logo, config paths)
- New ASCII art logo: ENTROPY MON
- Proper Python package structure: entropymon/{__init__,__main__,monitor}.py
- pyproject.toml with entry_points (pip install -> entropymon command)
- MIT license, README with full docs
- Works: pip install, entropymon CLI, python -m entropymon
- Optional nvidia extra: pip install entropymon[nvidia]
- --version flag added

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,7 @@
+__pycache__/
+*.pyc
+*.pyo
+*.egg-info/
+dist/
+build/
+.eggs/