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, 15 insertions, 14 deletions

diff --git a/packages/meshbay-hub/tests/test_hub_api.py b/packages/meshbay-hub/tests/test_hub_api.py
index 37e8e4f..9b73701 100644
--- a/packages/meshbay-hub/tests/test_hub_api.py
+++ b/packages/meshbay-hub/tests/test_hub_api.py
@@ -3,13 +3,11 @@ Integration tests for the Hub API.
 Uses SQLite in-memory + httpx.AsyncClient — no PostgreSQL, no network.
 """
 
-import base64
+from datetime import UTC
+
 import pytest
-import pytest_asyncio
 from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
 from cryptography.hazmat.primitives.asymmetric.x25519 import X25519PrivateKey
-from cryptography.hazmat.primitives import serialization
-
 from meshbay_common.crypto import pk_to_b64
 from meshbay_hub.api.deps import set_admin_usernames
 
@@ -32,7 +30,8 @@ async def _announce_signed(client, token: str) -> tuple[str, str]:
     The node key is independent of the user's identity key, so this mints a fresh
     one and signs the domain-separated announce message with it.
     """
-    import base64 as _b64, time as _t
+    import base64 as _b64
+    import time as _t
 
     me = await client.get("/v1/users/me",
                           headers={"Authorization": f"Bearer {token}"})
@@ -399,9 +398,10 @@ async def test_my_groups(client, db_session):
     # A group no node has announced is shown to its owner only — a member would
     # otherwise see a name they cannot open. Stamped here so the rest of this
     # test is about membership, which is what it was written for.
-    from datetime import datetime, timezone
+    from datetime import datetime
+
     from meshbay_hub.db.models import Group
-    (await db_session.get(Group, group_id)).hosted_at = datetime.now(timezone.utc)
+    (await db_session.get(Group, group_id)).hosted_at = datetime.now(UTC)
     await db_session.commit()
 
     # Re-login to get fresh token with group claims
@@ -434,7 +434,6 @@ async def test_my_groups(client, db_session):
 @pytest.mark.asyncio
 async def test_group_online_nodes(client):
     """GET /v1/groups/{id}/nodes returns online nodes serving the group."""
-    import json
     from meshbay_hub.api.revocation import _connected_nodes, _node_groups
 
     pk_ed, pk_x, _ = _gen_user_keys()
@@ -541,7 +540,7 @@ async def test_admin_can_revoke(client):
 @pytest.mark.asyncio
 async def test_email_encrypted_at_rest(client):
     """Email stored in DB must not contain plaintext address."""
-    from meshbay_hub.auth import encrypt_email, decrypt_email
+    from meshbay_hub.auth import decrypt_email, encrypt_email
     encrypted = encrypt_email("test@example.com")
     assert "@" not in encrypted
     assert decrypt_email(encrypted) == "test@example.com"
@@ -589,9 +588,10 @@ async def test_password_rehash_on_login(client, app):
         user = result.scalar_one()
         user.pw_version = 1
         # Re-hash with v1 params so verify_password(version=1) succeeds
-        from meshbay_hub.auth import _ARGON2_VERSIONS, _ARGON2_KEY_LEN, _ARGON2_LANES
-        from cryptography.hazmat.primitives.kdf.argon2 import Argon2id
         import os
+
+        from cryptography.hazmat.primitives.kdf.argon2 import Argon2id
+        from meshbay_hub.auth import _ARGON2_KEY_LEN, _ARGON2_LANES, _ARGON2_VERSIONS
         salt = os.urandom(16)
         params = _ARGON2_VERSIONS[1]
         pw_hash = Argon2id(
@@ -760,13 +760,14 @@ async def test_webrtc_signaling_roundtrip(client, app):
 @pytest.mark.asyncio
 async def test_ip_log_cleanup(app):
     """Old IP log entries are purged by cleanup task."""
-    from datetime import datetime, timezone, timedelta
+    from datetime import datetime, timedelta
+
     from meshbay_hub.db.engine import get_db
     from meshbay_hub.db.models import IPLog
     from meshbay_hub.tasks.cleanup import purge_old_ip_logs
 
     async for db in get_db():
-        old_ts = datetime.now(timezone.utc) - timedelta(days=400)
+        old_ts = datetime.now(UTC) - timedelta(days=400)
         db.add(IPLog(event="test_old", ip_address="1.2.3.4", timestamp=old_ts))
         db.add(IPLog(event="test_recent", ip_address="5.6.7.8"))
         await db.commit()
@@ -774,7 +775,7 @@ async def test_ip_log_cleanup(app):
         deleted = await purge_old_ip_logs(db, retention_days=365)
         assert deleted == 1
 
-        from sqlalchemy import select, func
+        from sqlalchemy import func, select
         count = (await db.execute(
             select(func.count()).where(IPLog.event.in_(["test_old", "test_recent"]))
         )).scalar_one()