feat(distribution): 默认结算冷却天数改为系统配置驱动

新建站点的默认冷却期原先硬编码 7 天（OnboardSite 字面量、DB 列默认、两套前端表单），
改一处要同时动三处。现统一到系统配置键 distribution.default_settlement_hold_days：

- systemconfig 注册该键（默认 7，0=立即释放，0-365 校验），纳入 admin 可见配置
- distribution 建站两条路径（CreateSite 未传值、OnboardSite 缺省）读取该配置，缺失或非法回落 7
- 新增 GET /admin/distribution/site-defaults 暴露当前有效默认值
- Vue / React 站点表单改为运行时拉取，拉取失败保持 7
- DB 列默认值保留作为兜底，站点级 settlement_hold_days 仍可单独覆盖

distribution-admin/src/api.ts

@@ -322,6 +322,18 @@ export async function listSites(): Promise<Site[]> {
   return extract(resp).items ?? []
 }
 
+export interface DistributionSiteDefaults {
+  default_settlement_hold_days: number
+}
+
+// fetchDistributionSiteDefaults 读取新建站点的默认结算冷却天数，供开通表单预填。
+export async function fetchDistributionSiteDefaults(): Promise<DistributionSiteDefaults> {
+  const resp = await api.get<ApiResponse<DistributionSiteDefaults>>(
+    '/admin/distribution/site-defaults'
+  )
+  return extract(resp)
+}
+
 export async function listRules(siteID?: number, mode?: string): Promise<Rule[]> {
   const resp = await api.get<ApiResponse<{ items: Rule[] }>>('/admin/distribution/rules', {
     params: { site_id: siteID || undefined, mode: mode || undefined },

distribution-admin/src/pages/Sites.tsx

@@ -17,7 +17,7 @@ import {
   Descriptions,
 } from 'antd'
 import { PlusOutlined, ShopOutlined, CopyOutlined } from '@ant-design/icons'
-import { listSites, onboardSite, type Site, type OnboardSitePayload, type OnboardSiteResult } from '../api'
+import { listSites, onboardSite, fetchDistributionSiteDefaults, type Site, type OnboardSitePayload, type OnboardSiteResult } from '../api'
 
 export default function Sites({ isSuperadmin = true }: { isSuperadmin?: boolean }) {
   const [items, setItems] = useState<Site[]>([])
@@ -25,6 +25,7 @@ export default function Sites({ isSuperadmin = true }: { isSuperadmin?: boolean
   const [modalOpen, setModalOpen] = useState(false)
   const [submitting, setSubmitting] = useState(false)
   const [successResult, setSuccessResult] = useState<OnboardSiteResult | null>(null)
+  const [defaultSettlementHoldDays, setDefaultSettlementHoldDays] = useState(7)
   const [form] = Form.useForm()
 
   const loadData = () => {
@@ -37,6 +38,16 @@ export default function Sites({ isSuperadmin = true }: { isSuperadmin?: boolean
 
   useEffect(() => {
     loadData()
+    fetchDistributionSiteDefaults()
+      .then((res) => {
+        const days = res?.default_settlement_hold_days
+        if (typeof days === 'number' && days >= 0 && days <= 365) {
+          setDefaultSettlementHoldDays(days)
+        }
+      })
+      .catch(() => {
+        // 拉取失败时保持内置默认值 7
+      })
   }, [])
 
   const handleOpenModal = () => {
@@ -46,7 +57,7 @@ export default function Sites({ isSuperadmin = true }: { isSuperadmin?: boolean
       display_account_enabled: true,
       tax_enabled: false,
       tax_rate_bps: 100,
-      settlement_hold_days: 7,
+      settlement_hold_days: defaultSettlementHoldDays,
     })
     setModalOpen(true)
   }
@@ -65,7 +76,7 @@ export default function Sites({ isSuperadmin = true }: { isSuperadmin?: boolean
         display_account_enabled: values.display_account_enabled,
         tax_enabled: values.tax_enabled,
         tax_rate_bps: values.tax_enabled ? values.tax_rate_bps : 0,
-        settlement_hold_days: Number(values.settlement_hold_days ?? 7),
+        settlement_hold_days: Number(values.settlement_hold_days ?? defaultSettlementHoldDays),
       }
       const res = await onboardSite(payload)
       message.success('分销站点及分销商管理员开通成功！')