fix(package): single-source Python SDK version

tests/test_version_contract.py

@@ -0,0 +1,18 @@
+from importlib.metadata import version
+
+import pytest
+
+from elydora import __version__
+from elydora.cli import build_parser
+
+
+def test_runtime_version_matches_distribution_metadata() -> None:
+    assert __version__ == version("elydora")
+
+
+def test_cli_reports_the_canonical_version(capsys: pytest.CaptureFixture[str]) -> None:
+    with pytest.raises(SystemExit) as exc_info:
+        build_parser().parse_args(["--version"])
+
+    assert exc_info.value.code == 0
+    assert capsys.readouterr().out == f"elydora {__version__}\n"