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, 0 insertions, 6 deletions

diff --git a/packages/meshbay-common/tests/test_js_python_parity.py b/packages/meshbay-common/tests/test_js_python_parity.py
index 9893a9f..3887414 100644
--- a/packages/meshbay-common/tests/test_js_python_parity.py
+++ b/packages/meshbay-common/tests/test_js_python_parity.py
@@ -21,7 +21,6 @@ import tempfile
 from pathlib import Path
 
 import pytest
-
 from meshbay_common.adminop import admin_transcript
 from meshbay_common.handshake import handshake_transcript, webrtc_binding
 from meshbay_common.join import join_transcript
@@ -312,7 +311,6 @@ def _groupbox_payload(idx: int) -> dict:
 @pytest.fixture(scope="module")
 def groupbox_js(tmp_path_factory):
     import msgpack
-
     from meshbay_common.groupbox import seal
 
     d = tmp_path_factory.mktemp("groupbox-parity")
@@ -486,7 +484,6 @@ def chatbox_js(tmp_path_factory):
     from cryptography.hazmat.primitives.asymmetric.ed25519 import (
         Ed25519PrivateKey,
     )
-
     from meshbay_common.chatbox import seal
 
     d = tmp_path_factory.mktemp("chatbox-parity")
@@ -537,7 +534,6 @@ def test_browser_opens_a_chat_message_python_sealed(idx, vector, chatbox_js):
 @pytest.mark.parametrize("idx,vector", list(enumerate(CHAT_VECTORS)))
 def test_python_opens_a_chat_message_the_browser_sealed(idx, vector, chatbox_js):
     import msgpack
-
     from meshbay_common.chatbox import open_message
 
     js, vectors = chatbox_js
@@ -580,7 +576,6 @@ def test_a_message_does_not_open_under_another_epoch(chatbox_js):
     would round-trip against itself and pass every other test here.
     """
     import pytest as _pytest
-
     from meshbay_common.chatbox import open_message
 
     _js, vectors = chatbox_js
@@ -598,7 +593,6 @@ def test_a_message_does_not_open_under_another_devices_key(chatbox_js):
     any coordination — the property per-device ratchet chains were wanted for.
     """
     import pytest as _pytest
-
     from meshbay_common.chatbox import open_message
 
     _js, vectors = chatbox_js