fix: serve legacy route aliases during cutover

tests/test_runtime.py

@@ -58,6 +58,21 @@ def test_production_readiness_fails_closed_for_ephemeral_backend() -> None:
     assert response.json()["checks"]["ephemeral_backend"] == "not_allowed"
 
 
+def test_protected_compatibility_readiness_requires_authorization_dependency() -> None:
+    settings = RuntimeSettings(
+        environment="test",
+        backend="memory",
+        allow_ephemeral=True,
+        v2_groups=frozenset({"registry"}),
+    )
+    response = TestClient(
+        create_app(settings=settings, port_store=InMemoryPortStore())
+    ).get("/readyz")
+
+    assert response.status_code == 503
+    assert response.json()["checks"]["authorization"] == "unavailable"
+
+
 def test_registry_validates_and_registers_idempotently() -> None:
     runtime = client()
     package = ops_hub_package()