feat: sync latest ARR implementation

tests/test_artifact_object_identity_migration.py

@@ -0,0 +1,34 @@
+from pathlib import Path
+import unittest
+
+
+PROJECT_ROOT = Path(__file__).resolve().parents[1]
+UP_PATH = PROJECT_ROOT / "database" / "011_artifact_object_identity.sql"
+DOWN_PATH = PROJECT_ROOT / "database" / "011_artifact_object_identity.down.sql"
+
+
+class ArtifactObjectIdentityMigrationTests(unittest.TestCase):
+    def test_forward_migration_replaces_content_uniqueness_with_lookup_index(self) -> None:
+        sql = UP_PATH.read_text(encoding="utf-8")
+
+        self.assertIn("current_database() <> 'booking_test'", sql)
+        self.assertIn("DROP CONSTRAINT artifacts_kind_hash_unique", sql)
+        self.assertIn("CREATE INDEX artifacts_kind_hash_idx", sql)
+        self.assertNotIn("CREATE UNIQUE INDEX artifacts_kind_hash_idx", sql)
+        self.assertNotIn("DROP SCHEMA", sql)
+
+    def test_rollback_refuses_after_repeated_content_is_registered(self) -> None:
+        sql = DOWN_PATH.read_text(encoding="utf-8")
+
+        self.assertIn("current_database() <> 'booking_test'", sql)
+        self.assertIn("GROUP BY artifact_kind, sha256", sql)
+        self.assertIn("HAVING count(*) > 1", sql)
+        self.assertIn(
+            "refusing rollback: repeated artifact content exists across storage identities",
+            sql,
+        )
+        self.assertIn("ADD CONSTRAINT artifacts_kind_hash_unique", sql)
+
+
+if __name__ == "__main__":
+    unittest.main()