fix: improve error message when uploading Excel file with incorrect column count

backend/common/utils/excel.py

@@ -0,0 +1,12 @@
+import pandas as pd
+
+def get_excel_column_count(file_path, sheet_name):
+    """获取Excel文件的列数"""
+    df_temp = pd.read_excel(
+        file_path,
+        sheet_name=sheet_name,
+        engine='calamine',
+        header=0,
+        nrows=0
+    )
+    return len(df_temp.columns)