feat(staff): 员工列表排序对齐云客API返回顺序(list_order列+抓取记序+API按序排)

- wechat_account 加 list_order 列(云客 wxUser/list 返回顺序)
- 抓取器记录每行在API响应中的序号
- /api/accounts ORDER BY list_order(对齐云客员工列表排列)

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

yunke-server/app/db/models.py

@@ -166,6 +166,8 @@ class WechatAccount(Base):
     last_update: Mapped[int | None] = mapped_column(BigInteger, nullable=True)
 
     version: Mapped[str | None] = mapped_column(String(64), nullable=True)
+    # 云客 wxUser/list 返回顺序(对齐云客员工列表排列;NULL=未回填按 wx_id 排)
+    list_order: Mapped[int | None] = mapped_column(Integer, nullable=True)
     raw_json: Mapped[dict[str, Any] | None] = mapped_column(JSON, nullable=True)
     fetched_at: Mapped[dt.datetime] = _fetched_at()
     updated_at: Mapped[dt.datetime] = _updated_at()