feat(packaging): make setup-hibernate a pip-installable Python package

- add pyproject.toml with setuptools build system
- add console script entry point `setup-hibernate`
- migrate main.py to src/setup_hibernate/__main__.py
- add MIRRORS file with Git and PyPI endpoints
- enable PEP 621 metadata and src layout

https://chatgpt.com/share/6964c8c0-8b94-800f-be8e-10c4fc8a2f30

MIRRORS

@@ -0,0 +1,4 @@
+git@github.com:kevinveenbirkenbach/setup-hibernate.git
+ssh://git@git.veen.world:2201/kevinveenbirkenbach/setup-hibernate.git
+ssh://git@code.infinito.nexus:2201/kevinveenbirkenbach/setup-hibernate.git
+https://pypi.org/project/setup-hibernate/

pyproject.toml

@@ -0,0 +1,34 @@
+[build-system]
+requires = ["setuptools>=69", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "setup-hibernate"
+version = "0.1.0"
+description = "Configure Linux hibernation (swapfile, GRUB resume, mkinitcpio resume hook)."
+readme = "README.md"
+requires-python = ">=3.8"
+license = { file = "LICENSE" }
+authors = [{ name = "Kevin Veen-Birkenbach" }]
+keywords = ["hibernate", "hibernation", "swap", "grub", "mkinitcpio", "linux", "arch", "manjaro"]
+classifiers = [
+  "License :: OSI Approved :: MIT License",
+  "Programming Language :: Python :: 3",
+  "Programming Language :: Python :: 3 :: Only",
+  "Operating System :: POSIX :: Linux",
+  "Environment :: Console",
+]
+
+[project.urls]
+Homepage = "https://www.veen.world"
+Repository = "https://github.com/kevinveenbirkenbach/setup-hibernate"
+Issues = "https://github.com/kevinveenbirkenbach/setup-hibernate/issues"
+
+[project.scripts]
+setup-hibernate = "setup_hibernate.__main__:main"
+
+[tool.setuptools]
+package-dir = { "" = "src" }
+
+[tool.setuptools.packages.find]
+where = ["src"]