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/hedgedoc/functional/test_branding.py

@@ -14,7 +14,6 @@ import urllib.request
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "..", "runner"))
 from harness import http as harness_http  # noqa: E402
 
-
 _CTX = ssl.create_default_context()
 _CTX.check_hostname = False
 _CTX.verify_mode = ssl.CERT_NONE

tests/hedgedoc/functional/test_health_check.py

@@ -15,7 +15,5 @@ from harness import http as harness_http  # noqa: E402
 def test_hedgedoc_root_serves(live_app):
     """GET / → 200 or 302 (login/new redirect)."""
     url = f"https://{live_app}/"
-    status, _ = harness_http.retry_http_get(
-        url, expect_status=(200, 302), max_wait=90, interval=5
-    )
+    status, _ = harness_http.retry_http_get(url, expect_status=(200, 302), max_wait=90, interval=5)
     assert status in (200, 302), f"GET {url} HTTP {status} (expected 200 or 302)"