style: ruff's own fixes, mechanically applied

`ruff check .` had gone unrun long enough to report 568 errors, which is the
same as having no linter: the next real finding would have been invisible in the
noise. This is the 521 it fixes by itself, in 173 files, and nothing else — the
98 it cannot fix are the next commit.

What actually changed: import sorting (225), imports nobody used (87, none of
them a re-export — no `__init__.py` is touched, which was the one way this could
have broken an import elsewhere), `datetime.timezone.utc` to `datetime.UTC` (69)
and `asyncio.TimeoutError` to `TimeoutError` (18), both plain aliases on the 3.12
this project requires, `Optional[X]` to `X | None` (24), and f-strings with
nothing to interpolate (19).

Checked rather than assumed: every module in the three packages still imports,
and the suite is 2893 passed — the same count, test for test, as the merge
before it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/packages/meshbay-hub/tests/test_group_purge.py b/packages/meshbay-hub/tests/test_group_purge.py
index 0611dba..e729297 100644
--- a/packages/meshbay-hub/tests/test_group_purge.py
+++ b/packages/meshbay-hub/tests/test_group_purge.py
@@ -21,13 +21,18 @@ from datetime import UTC, datetime, timedelta
 
 import jwt
 import pytest
-from sqlalchemy import delete, func, select, text
-from sqlalchemy.exc import IntegrityError
-
 from meshbay_hub.db.models import (
-    ContentReport, EmailVerification, Group, GroupMember, IPLog, Notification, User,
+    ContentReport,
+    EmailVerification,
+    Group,
+    GroupMember,
+    IPLog,
+    Notification,
+    User,
 )
 from meshbay_hub.db.purge import _referencing
+from sqlalchemy import delete, func, select, text
+from sqlalchemy.exc import IntegrityError
 
 SEEDED = {"group_members", "notifications", "email_verifications", "content_reports"}