fix(cost-center): 禁止追溯改价，改价只能当前或未来生效

- 后端统一校验：retroactive 请求直接拒绝，effectiveFrom 早于当前时间拒绝
- 去掉「追溯至历史订单」入口，改价只影响之后的新订单
- 历史订单成本与成交价由快照固化，不再受改价影响

apps/backend/src/services/cost-center/affiliate-product-service.ts

@@ -1,6 +1,7 @@
 import { query } from '../../db/client.js'
 import type { AdminSession } from '../admin/admin-auth-service.js'
 import type { JsonObject } from '../../types/json.js'
+import { resolvePriceEffectiveFrom } from './cost-center-normalizers.js'
 import { createHttpError } from '../../utils/http.js'
 import { formatShanghaiDate, shiftDate } from '../../utils/finance-date-range.js'
 import { nowIso } from '../../utils/time.js'
@@ -304,11 +305,7 @@ export async function setAdminAffiliateProductPrice(
   }
 
   const now = nowIso()
-  let effectiveFrom = payload.effectiveFrom ? String(payload.effectiveFrom) : now
-  if (payload.retroactive === true || payload.retroactive === 'true') {
-    const today = formatShanghaiDate(new Date())
-    effectiveFrom = shiftDate(today, -30) + 'T00:00:00+08:00'
-  }
+  const effectiveFrom = resolvePriceEffectiveFrom(payload)
   const changeReason = String(payload.changeReason || '配置自动发货采购成本').trim()
 
   const existingResult = await query<{ id: number; amount_fen: number; effective_from: string }>(

apps/backend/src/services/cost-center/cost-center-normalizers.ts

@@ -246,3 +246,32 @@ export function requiredRow<T>(row: T | undefined | null, message: string): T {
   }
   return row
 }
+
+/**
+ * 成本改价的生效时间：只允许当前或未来，不允许追溯。
+ * 历史订单的成本与成交价已固化在快照里，改价不得回写过去。
+ */
+export function resolvePriceEffectiveFrom(payload: Record<string, unknown>): string {
+  if (payload.retroactive === true || payload.retroactive === 'true') {
+    throw createHttpError('成本改价不支持追溯历史订单；历史订单成本已固化', {
+      statusCode: 400,
+      errorCode: 'cost_retroactive_not_allowed',
+    })
+  }
+  const raw = payload.effectiveFrom ?? payload.effective_from
+  if (!raw) return new Date().toISOString()
+  const time = Date.parse(String(raw))
+  if (!Number.isFinite(time)) {
+    throw createHttpError('生效时间格式无效', {
+      statusCode: 400,
+      errorCode: 'cost_effective_from_invalid',
+    })
+  }
+  if (time < Date.now() - 60_000) {
+    throw createHttpError('生效时间不能早于当前时间；历史订单成本已固化', {
+      statusCode: 400,
+      errorCode: 'cost_effective_from_in_past',
+    })
+  }
+  return new Date(time).toISOString()
+}

apps/backend/src/services/cost-center/product-catalog-service.ts

@@ -16,6 +16,7 @@ import { nowIso } from '../../utils/time.js'
 import { normalizeMatchText, normalizeSkuSeriesEquivalence } from '../product-match/normalize.js'
 import { resolveSkuNameQuantity } from '../product-match/pricing.js'
 import { setAdminAffiliateProductPrice } from './affiliate-product-service.js'
+import { resolvePriceEffectiveFrom } from './cost-center-normalizers.js'
 import { ensureVoucherRuleForSku } from '../fulfillment/channel-assign-service.js'
 import { syncAdminWorkProductRulePrice } from '../worker-platform/admin-worker-catalog-service.js'
 import {
@@ -1367,11 +1368,7 @@ export async function setAdminProductPrice(
   }
 
   const now = nowIso()
-  let effectiveFrom = payload.effectiveFrom ? String(payload.effectiveFrom) : now
-  if (payload.retroactive === true || payload.retroactive === 'true') {
-    const today = formatShanghaiDate(new Date())
-    effectiveFrom = shiftDate(today, -30) + 'T00:00:00+08:00'
-  }
+  const effectiveFrom = resolvePriceEffectiveFrom(payload)
   const changeReason = String(payload.changeReason || '在商品与成本中心统一调整价格').trim()
 
   // 2. 如果是接单模板商品 (tpl:)