Restructure: make a proper package and entrypoint

pyproject.toml

@@ -15,6 +15,9 @@ dependencies = [
     "tqdm>=4.65.0",
 ]
 
+[project.scripts]
+nctool = "nctool.__main__:main"
+
 [tool.pdm.dev-dependencies]
 dev = [
     "ruff>=0.0.261",

src/nctool/__main__.py

+from . import cli
+
+
+def main():
+    cli.main()
+
+
+if __name__ == "__main__":
+    main()

nctool.py → src/nctool/cli.py

-#! /usr/bin/env python
 import argparse
 from getpass import getpass
 import os
@@ -69,7 +68,7 @@ def get_models(args):
                 fp.write(r.data)
 
 
-if __name__ == "__main__":
+def main():
     parser = argparse.ArgumentParser()
 
     parser.add_argument(