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/concurrency/test_locks.py

@@ -61,9 +61,9 @@ def test_3_lock_fd_not_inherited_by_children(lock_dir, pool):
     p.kill()
     p.wait(timeout=10)
     assert os.path.exists(f"/proc/{child_pid}"), "child should outlive the holder"
-    assert (
-        wait_lock_state(DOMAIN, "free") == "free"
-    ), "lock must release on holder death even with a live child (PEP 446 non-inheritable fd)"
+    assert wait_lock_state(DOMAIN, "free") == "free", (
+        "lock must release on holder death even with a live child (PEP 446 non-inheritable fd)"
+    )
 
 
 def test_4_second_acquire_blocks_until_first_exits(lock_dir, pool):