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, 10 insertions, 11 deletions

diff --git a/packages/meshbay-hub/tests/test_group_hosting.py b/packages/meshbay-hub/tests/test_group_hosting.py
index c571771..c6111f2 100644
--- a/packages/meshbay-hub/tests/test_group_hosting.py
+++ b/packages/meshbay-hub/tests/test_group_hosting.py
@@ -14,13 +14,12 @@ deleted every group during a hub restart.
 
 import base64
 import hashlib
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 
 import pytest
-from sqlalchemy import select
-
 from meshbay_hub.db.models import Group, GroupMember
 from meshbay_hub.tasks.cleanup import find_unhosted_groups, prune_unhosted_groups
+from sqlalchemy import select
 
 
 def _auth_key(password: str, username: str) -> str:
@@ -49,7 +48,7 @@ async def _group(client, owner, name, visibility="private", join_policy=None):
 
 async def _mark_hosted(db_session, group_id, when=None):
     g = await db_session.get(Group, group_id)
-    g.hosted_at = when or datetime.now(timezone.utc)
+    g.hosted_at = when or datetime.now(UTC)
     await db_session.commit()
 
 
@@ -134,7 +133,7 @@ async def test_an_unhosted_group_past_the_grace_period_is_collected(client, db_s
     gid = (await _group(client, owner, "abandoned")).json()["group_id"]
 
     g = await db_session.get(Group, gid)
-    g.created_at = datetime.now(timezone.utc) - timedelta(days=8)
+    g.created_at = datetime.now(UTC) - timedelta(days=8)
     await db_session.commit()
 
     gone = await prune_unhosted_groups(db_session)
@@ -149,8 +148,8 @@ async def test_an_old_group_that_was_hosted_is_never_collected(client, db_sessio
     gid = (await _group(client, owner, "long-lived")).json()["group_id"]
 
     g = await db_session.get(Group, gid)
-    g.created_at = datetime.now(timezone.utc) - timedelta(days=400)
-    g.hosted_at = datetime.now(timezone.utc) - timedelta(days=399)
+    g.created_at = datetime.now(UTC) - timedelta(days=400)
+    g.hosted_at = datetime.now(UTC) - timedelta(days=399)
     await db_session.commit()
 
     assert await find_unhosted_groups(db_session) == []
@@ -161,7 +160,7 @@ async def test_dry_run_reports_without_deleting(client, db_session):
     owner = await _user(client, "reaper4_test")
     gid = (await _group(client, owner, "still-here")).json()["group_id"]
     g = await db_session.get(Group, gid)
-    g.created_at = datetime.now(timezone.utc) - timedelta(days=30)
+    g.created_at = datetime.now(UTC) - timedelta(days=30)
     await db_session.commit()
 
     gone = await prune_unhosted_groups(db_session, dry_run=True)
@@ -178,7 +177,7 @@ async def test_collecting_a_group_takes_its_memberships_with_it(client, db_sessi
     await client.post(f"/v1/groups/{gid}/members/tagalong", json={}, headers=owner)
 
     g = await db_session.get(Group, gid)
-    g.created_at = datetime.now(timezone.utc) - timedelta(days=9)
+    g.created_at = datetime.now(UTC) - timedelta(days=9)
     await db_session.commit()
 
     await prune_unhosted_groups(db_session)
@@ -247,7 +246,7 @@ async def test_the_stamp_is_not_moved_by_a_later_reconnection(client, db_session
 
     owner = await _user(client, "stamped2")
     gid = (await _group(client, owner, "steady")).json()["group_id"]
-    first = datetime.now(timezone.utc) - timedelta(days=30)
+    first = datetime.now(UTC) - timedelta(days=30)
     await _mark_hosted([gid])
     g = await db_session.get(Group, gid)
     g.hosted_at = first
@@ -259,7 +258,7 @@ async def test_the_stamp_is_not_moved_by_a_later_reconnection(client, db_session
     await db_session.refresh(g)
     # SQLite hands back a naive datetime where PostgreSQL keeps the offset, so
     # the comparison is made on common ground rather than on the driver.
-    stored = g.hosted_at.replace(tzinfo=timezone.utc) if g.hosted_at.tzinfo is None \
+    stored = g.hosted_at.replace(tzinfo=UTC) if g.hosted_at.tzinfo is None \
         else g.hosted_at
     assert abs((stored - first).total_seconds()) < 1, "the stamp moved"