style: repo-wide lint pass — make the lint gate green again

Push builds have been RED on the lint step since ~build 209 from accumulated
formatting drift. This is the mechanical cleanup: ruff format + ruff --fix
(UP038 isinstance unions, SIM105 contextlib.suppress, UP031 f-strings, SIM115
tempfile context manager), shfmt -i 2 -ci, nixpkgs-fmt/statix/deadnix (merged
attrsets, dropped unused lib args), yamllint, and shell quoting fixes in
tests/lasuite-docs/setup_custom_tests.sh. No behaviour changes intended;
lint: PASS, unit tests: 138 passed.

tests/n8n/functional/test_login_state.py

@@ -91,6 +91,6 @@ def test_login_endpoint_returns_json(live_app):
     assert body is not None, f"/rest/login returned no parseable JSON: state={state}"
     # If it's a dict, it's the expected envelope; if it's a list, n8n shouldn't do that on this
     # endpoint, but accept either; only reject obvious non-shapes.
-    assert isinstance(body, (dict, list)), (
-        f"/rest/login returned unexpected JSON type {type(body).__name__}: {body!r}"
-    )
+    assert isinstance(
+        body, dict | list
+    ), f"/rest/login returned unexpected JSON type {type(body).__name__}: {body!r}"