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/bluesky-pds/functional/test_session_auth.py

@@ -30,6 +30,6 @@ def test_get_session_requires_auth(live_app):
         f"body: {body!r}"
     )
     # The XRPC error envelope is JSON with an `error` field per the atproto spec.
-    assert isinstance(body, dict) and body.get("error"), (
-        f"expected XRPC JSON error envelope; got: {body!r}"
-    )
+    assert isinstance(body, dict) and body.get(
+        "error"
+    ), f"expected XRPC JSON error envelope; got: {body!r}"