feat(fulfillment): 渠道联动与管道兜底

- 人工配置保存/删除同步渠道规则，人工确认写 channel/status
- 按 SKU 指定渠道默认同时落规则
- 管道补充：载体缺失、人工成本未记录、事实与总账按水位追赶

apps/backend/src/services/fulfillment/channel-assign-service.ts

@@ -371,7 +371,8 @@ export async function assignChannelBySku(input: {
   channel: string
   adminUserId: number | null
   note?: string
-}): Promise<{ updated: number }> {
+  createRule?: boolean
+}): Promise<{ updated: number; ruleCreated: boolean }> {
   if (!isFulfillmentChannel(input.channel)) {
     throw createHttpError('渠道无效', { statusCode: 400, errorCode: 'invalid_channel' })
   }
@@ -395,7 +396,26 @@ export async function assignChannelBySku(input: {
     `,
     [input.provider, input.shopId, input.skuCode, input.channel, input.adminUserId],
   )
-  return { updated: result.rowCount || 0 }
+
+  // 默认同时落一条渠道规则：否则同 SKU 的下一单还是会进待分类。
+  let ruleCreated = false
+  if (input.createRule !== false) {
+    const rule = await upsertChannelRule({
+      provider: input.provider,
+      shopId: input.shopId,
+      matchKeyType: 'sku_code',
+      matchKey: input.skuCode,
+      channel: input.channel,
+      priority: 10,
+      source: 'operator',
+      enabled: true,
+      note: `运营在待分类队列指定：${String(input.note || '').slice(0, 120)}`,
+      adminUserId: input.adminUserId,
+    })
+    ruleCreated = rule.id > 0
+  }
+
+  return { updated: result.rowCount || 0, ruleCreated }
 }
 
 export async function listChannelRules(