Fix pyproject.toml: use setuptools.build_meta, add project.scripts entry point

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
 requires = ["setuptools>=68", "wheel"]
-build-backend = "setuptools.backends.legacy:build"
+build-backend = "setuptools.build_meta"
 
 [project]
 name = "pm_ops"
@@ -13,6 +13,9 @@ dependencies = [
     "pydantic>=2.0.0",
 ]
 
+[project.scripts]
+server = "server.app:main"
+
 [tool.setuptools]
 packages = ["pm_ops", "pm_ops.server", "pm_ops.server.apps", "pm_ops.server.world", "pm_ops.server.tasks", "pm_ops.server.verifiers"]