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_rest_settings.py

@@ -72,9 +72,9 @@ def test_rest_settings_returns_json_with_known_keys(live_app):
     # (e.g. version 3.2.0+2.20.6).
     assert isinstance(body, dict), f"/rest/settings returned non-dict JSON: {type(body).__name__}"
     data = body.get("data") if "data" in body else body
-    assert isinstance(data, dict), (
-        f"/rest/settings response missing 'data' envelope: keys={list(body.keys())[:10]}"
-    )
+    assert isinstance(
+        data, dict
+    ), f"/rest/settings response missing 'data' envelope: keys={list(body.keys())[:10]}"
     # Bootstrap keys the editor SPA relies on across versions:
     #   - `userManagement`: the auth-mode dict (whether owner-setup is needed, smtp/email mode).
     #   - `defaultLocale`: i18n bootstrap; present on every n8n install.