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/discourse/custom/test_create_topic.py

@@ -48,23 +48,23 @@ def test_create_topic_roundtrip(live_app):
         headers=hdrs,
         timeout=60,
     )
-    assert status in (200, 201) and isinstance(
-        body, dict
-    ), f"create topic failed: HTTP {status}, body={body!r}"
+    assert status in (200, 201) and isinstance(body, dict), (
+        f"create topic failed: HTTP {status}, body={body!r}"
+    )
     topic_id = body.get("topic_id")
     assert topic_id, f"create topic returned no topic_id: {body!r}"
 
     # 4) Read the topic back and assert title + first-post body round-trip.
     status, got = harness_http.http_get(f"{base}/t/{topic_id}.json", headers=hdrs, timeout=30)
-    assert status == 200 and isinstance(
-        got, dict
-    ), f"read topic failed: HTTP {status}, body={got!r}"
-    assert (
-        got.get("title") == title
-    ), f"topic title did not round-trip: sent {title!r}, got {got.get('title')!r}"
+    assert status == 200 and isinstance(got, dict), (
+        f"read topic failed: HTTP {status}, body={got!r}"
+    )
+    assert got.get("title") == title, (
+        f"topic title did not round-trip: sent {title!r}, got {got.get('title')!r}"
+    )
     posts = (got.get("post_stream") or {}).get("posts") or []
     assert posts, f"topic has no posts on read-back: {got!r}"
     first_cooked = posts[0].get("cooked", "")
-    assert (
-        marker in first_cooked
-    ), f"topic body did not round-trip: marker {marker!r} not in first post {first_cooked!r}"
+    assert marker in first_cooked, (
+        f"topic body did not round-trip: marker {marker!r} not in first post {first_cooked!r}"
+    )