fix: format test file and remove unused imports

- Collapse multi-line io.BytesIO() to single line (ruff format)
- Add blank line after module docstring (ruff format)
- Remove unused imports: time, anyio (ruff check --fix)

Author: Nova

tests/server/test_stdio_2678.py

@@ -5,13 +5,12 @@
 read_stream_writer in stdin_reader's finally block so the server sees EOF and
 can flush pending writes before the task group exits.
 """
+
 import io
 import sys
 import threading
-import time
 from io import TextIOWrapper
 
-import anyio
 import pytest
 
 from mcp.server.mcpserver import MCPServer
@@ -46,9 +45,7 @@ def test_stdio_response_not_dropped_on_eof(monkeypatch: pytest.MonkeyPatch) -> N
     the server could flush its response through stdout_writer.
     """
     ping = JSONRPCRequest(jsonrpc="2.0", id=1, method="ping")
-    stdin_bytes = io.BytesIO(
-        ping.model_dump_json(by_alias=True, exclude_none=True).encode() + b"\n"
-    )
+    stdin_bytes = io.BytesIO(ping.model_dump_json(by_alias=True, exclude_none=True).encode() + b"\n")
     captured = _KeepOpenBytesIO()
     monkeypatch.setattr(sys, "stdin", TextIOWrapper(stdin_bytes, encoding="utf-8"))
     monkeypatch.setattr(sys, "stdout", TextIOWrapper(captured, encoding="utf-8"))