feat: AI历史记录、企业信息seed、员工状态自动刷新、风险预测数据准确性优化

- 智能问答/风险预测/合同审查/案例匹配 均支持历史记录保存、加载、删除
- 后端 predict/predict-stream 补充离职记录详情和预计算工龄/天数，避免AI计算错误
- Organization 增加 contactName/contactPhone 字段，seed 企业信息
- Settings 页面修复 orgData/usersData 取值路径错误
- Roster/Termination/Contracts mutation 增加 roster cache invalidation
- 员工档案页面 tab 固定、内容区域滚动到窗口底部
- 解聘证据链显示逻辑修复（协商一致离职 vs 员工主动离职）

frontend/src/pages/Settings.tsx

@@ -97,12 +97,12 @@ function OrgSettings({ orgData, onSave, saving }: { orgData: any; onSave: (data:
   })
 
   useEffect(() => {
-    if (orgData?.data) {
+    if (orgData) {
       setForm({
-        name: orgData.data.name || '',
-        contactName: orgData.data.contactName || '',
-        contactPhone: orgData.data.contactPhone || '',
-        payrollFrequency: orgData.data.payrollFrequency || 1,
+        name: orgData.name || '',
+        contactName: orgData.contactName || '',
+        contactPhone: orgData.contactPhone || '',
+        payrollFrequency: orgData.payrollFrequency || 1,
       })
     }
   }, [orgData])
@@ -146,7 +146,7 @@ function UserSettings({ usersData }: { usersData: any }) {
   const queryClient = useQueryClient()
   const [showAddModal, setShowAddModal] = useState(false)
   const [editingUser, setEditingUser] = useState<any>(null)
-  const users = usersData?.data || []
+  const users = usersData || []
 
   const updateMutation = useMutation({
     mutationFn: ({ id, data }: { id: string; data: any }) => api.put(`/settings/users/${id}`, data),
@@ -411,7 +411,7 @@ function ExportSettings() {
 
 function PlanSettings({ orgData }: { orgData: any }) {
   const queryClient = useQueryClient()
-  const plan = orgData?.data?.plan || 'FREE'
+  const plan = orgData?.plan || 'FREE'
 
   const { data: usageData } = useQuery<any>({
     queryKey: ['usage'],