style(test): Move Pane import to file top per PEP 8

Follow PEP 8 guidelines by moving the openpyxl.worksheet.views.Pane
import from inside the test function to the top of the file with
other imports.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: k-ibaraki

tests/test_sharepoint_excel.py

@@ -6,6 +6,7 @@
 import pytest
 from openpyxl import Workbook
 from openpyxl.styles import Font, PatternFill
+from openpyxl.worksheet.views import Pane
 
 from src.sharepoint_excel import SharePointExcelParser
 
@@ -788,8 +789,6 @@ def test_split_pane_is_ignored(self):
         ws["A2"] = "Data"
 
         # split paneを設定（frozenではなくsplit）
-        from openpyxl.worksheet.views import Pane
-
         ws.sheet_view.pane = Pane(ySplit=3, xSplit=0, state="split")
 
         excel_bytes = BytesIO()