ci: verify checkpoint portability on Windows

tests/test_ci_policy.py

@@ -110,3 +110,21 @@ def test_ci_retains_normalized_test_and_quality_trends_for_ninety_days():
     assert "test-trend-py${{ matrix.python-version }}.json" in workflow
     assert "quality-trend-py3.12.json" in workflow
     assert workflow.count("retention-days: 90") >= 2
+
+
+def test_ci_runs_checkpoint_portability_contracts_on_windows():
+    workflow = WORKFLOW.read_text(encoding="utf-8")
+    checkpoint_job = workflow.split("  checkpoint-windows:\n", maxsplit=1)[1].split(
+        "  quality-depth:\n",
+        maxsplit=1,
+    )[0]
+
+    assert "runs-on: windows-latest" in checkpoint_job
+    assert 'python-version: "3.12"' in checkpoint_job
+    assert "uv sync --locked --no-default-groups --extra dev --no-editable" in checkpoint_job
+    assert "tests/test_checkpoint_atomicity.py" in checkpoint_job
+    assert "tests/test_persistence_contracts.py" in checkpoint_job
+    assert "tests/test_persistence_pipeline.py" in checkpoint_job
+    assert "--no-cov" in checkpoint_job
+    assert "checkpoint-evidence-windows-py3.12" in checkpoint_job
+    assert "if-no-files-found: error" in checkpoint_job