朱子纯 / test

- Remove the green '已绑定' badge from StaffPicker; the prototype
  doesn't show one and it's confusing in create mode (nothing has
  been saved yet).
- On staff selection, auto-fill 用户号 (sUserNo) and 用户名 (sUserName)
  with the staff's Chinese name to match prototype behavior; user
  can still override either field after selection.

Backend:
- StaffSearchVO (iIncrement / sStaffNo / sStaffName / sDepartment)
- StaffMapper.searchActive(keyword, limit) — LIKE on name + staff no
- StaffController GET /api/usr/staffs?keyword=&limit=
- UserListVO + UserMapper.xml: expose iStaffId so edit mode preserves
  the binding when user doesn't change 员工名

Frontend:
- api/staff.ts → searchStaff()
- StaffPicker.tsx: input + dropdown with debounced search, '已绑定'
  badge when an iStaffId is bound, click outside to close, search icon
- UserDetail: replace 员工名 PrimInput with StaffPicker; track iStaffId
  in form state; send to backend on save (no longer omitted)