lint: ruff format + one auto-fix so the push self-test is green again

`scripts/lint.sh --fix` from the pinned lint devshell: 90 Python files
reformatted (ruff format, mechanical) and one C420 (dict comprehension →
dict.fromkeys) in tests/unit/test_f211_sso_skip.py. The push self-test had
been failing at the lint stage since build 1313 (2026-08-31) on exactly
these files; nothing else changed.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FqkQq3CDmFWcQ7u1LzoyRz

tests/custom-html-tiny/custom/test_serves_content.py

@@ -79,9 +79,9 @@ def test_static_file_roundtrip_and_404(live_app):
         # A random non-existent path must 404 — proves real static-file semantics, distinguishing a
         # working server from a 200-everything stub or a mis-routed Traefik fallback.
         miss_status, _ = _get(f"https://{live_app}/ccci-missing-{uuid.uuid4().hex}.txt")
-        assert (
-            miss_status == 404
-        ), f"missing path returned {miss_status} (expected 404 — generic 200-returner / mis-route?)"
+        assert miss_status == 404, (
+            f"missing path returned {miss_status} (expected 404 — generic 200-returner / mis-route?)"
+        )
     finally:
         with contextlib.suppress(OSError):
             os.remove(path)