Refactor DockerComposeManager usage in basic_example and enhance error handling for service, network, config, and secret management

tests/test_compose_manager.py

@@ -71,12 +71,8 @@ def test_modify_nonexistent_service(tmp_path: Path) -> None:
 def test_remove_nonexistent_service(tmp_path: Path) -> None:
     compose_file: Path = tmp_path / "docker-compose.yml"
     manager = DockerComposeManager(str(compose_file))
-    # Should not raise
-    manager.remove_service("notfound").save()
-    with compose_file.open() as f:
-        data = yaml.safe_load(f)
-    assert "services" in data
-    assert data["services"] == {}
+    with pytest.raises(KeyError):
+        manager.remove_service("notfound")
 
 
 def test_create_service_with_extra_kwargs(tmp_path: Path) -> None: