refactor: convert script to automtu package with CI workflow

https://chatgpt.com/share/697112b2-0410-800f-93ff-9372b603d43f

tests/unit/test___main__.py

@@ -0,0 +1,26 @@
+import unittest
+from unittest.mock import Mock, patch
+
+import automtu.__main__ as entry
+
+
+class TestMain(unittest.TestCase):
+    def test_main_calls_parser_and_core(self) -> None:
+        fake_args = object()
+        fake_parser = Mock()
+        fake_parser.parse_args.return_value = fake_args
+
+        with (
+            patch("automtu.__main__.build_parser", return_value=fake_parser) as p_build,
+            patch("automtu.__main__.run_automtu", return_value=0) as p_run,
+        ):
+            rc = entry.main()
+
+        self.assertEqual(rc, 0)
+        p_build.assert_called_once_with()
+        fake_parser.parse_args.assert_called_once_with()
+        p_run.assert_called_once_with(fake_args)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)