feat: add greet CLI with tests

pyproject.toml

@@ -0,0 +1,31 @@
+[project]
+name = "py-demo"
+version = "0.1.0"
+description = "Add your description here"
+readme = "README.md"
+authors = [
+    { name = "Brian Rosner", email = "brian@brosner.com" }
+]
+requires-python = ">=3.13"
+dependencies = [
+    "click>=8.3.1",
+]
+
+[project.scripts]
+py-demo = "py_demo.cli:main"
+
+[build-system]
+requires = ["uv_build>=0.10.4,<0.11.0"]
+build-backend = "uv_build"
+
+[dependency-groups]
+dev = [
+    "pytest>=9.0.2",
+    "ruff>=0.15.7",
+]
+
+[tool.ruff]
+line-length = 88
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]