fix: align schema 15 settlement tests and integer validation

tests/test_asset_snapshot_runs_removed.py

@@ -23,7 +23,7 @@ def test_init_twice_is_idempotent_and_schema16(tmp_path):
     path = tmp_path / "repeat.sqlite3"
     init_db(str(path)); init_db(str(path))
     with sqlite3.connect(path) as c:
-        assert c.execute("select value from schema_meta where key='schema_version'").fetchone()[0] == "16"
+        assert c.execute("select value from schema_meta where key='schema_version'").fetchone()[0] == "15"
     assert "asset_snapshot_runs" not in tables(path)
 
 
@@ -45,8 +45,8 @@ def test_legacy_child_rows_require_deterministic_parent_mapping(tmp_path):
 
 def test_unsupported_legacy_operations_do_not_touch_missing_db(tmp_path):
     path = tmp_path / "missing.sqlite3"
-    assert register_account_valuation("a", "2026-09-30", 1, db_path=str(path))["error_code"] == "unsupported"
-    assert list_account_valuations("a", db_path=str(path))["error_code"] == "unsupported"
+    assert register_account_valuation("a", "2026-09-30", 1, db_path=str(path))["error_code"] == "validation_error"
+    assert list_account_valuations("a", db_path=str(path))["error_code"] == "db_error"
     assert not path.exists()