支持结账多轮协商与按实际消耗双比例结算

允许双方最多 6 轮修改结账方案；哈夫币按实际消耗与 buyer/seller 比例计价，打超从押金扣，押金不足禁止自动完结并引导人工争议。同步收紧结账明细展示密度。

frontend/src/features/orders/composables/useOrderActions.ts

@@ -191,6 +191,34 @@ export function useOrderActions(options: UseOrderActionsOptions) {
       'abnormal',
     ].includes(order.value.status)
   })
+  const canCounterCheckout = computed(() => {
+    if (!order.value?.checkout) return false
+    return Boolean(order.value.checkout.can_counter)
+  })
+  const canAcceptCheckoutProposal = computed(() => {
+    if (!order.value?.checkout) return false
+    // 后端 can_accept 已含 shortfall 校验；无字段时按角色状态兜底
+    if (typeof order.value.checkout.can_accept === 'boolean') {
+      return order.value.checkout.can_accept
+    }
+    return (
+      (isOwner.value && order.value.status === 'pending_checkout_confirm') ||
+      (isRenter.value && order.value.status === 'pending_checkout_accept')
+    )
+  })
+  const checkoutShortfallCent = computed(() =>
+    Number(order.value?.checkout?.shortfall_cent || 0)
+  )
+  const checkoutOvershootCent = computed(() =>
+    Number(order.value?.checkout?.overshoot_amount_cent || 0)
+  )
+  const checkoutRoundLabel = computed(() => {
+    const c = order.value?.checkout
+    if (!c) return ''
+    const round = Number(c.round_count || 1)
+    const max = Number(c.max_rounds || 6)
+    return `第 ${round}/${max} 轮协商`
+  })
   const canCancelDispute = computed(() => {
     return (
       !!order.value &&
@@ -365,6 +393,10 @@ export function useOrderActions(options: UseOrderActionsOptions) {
 
   async function handleConfirmCheckout() {
     if (!order.value) return
+    if (checkoutShortfallCent.value > 0) {
+      options.notifyWarning('押金不足以覆盖打超/赔付，无法自动完结，请修改方案或发起争议由人工处理')
+      return
+    }
     if (needsConfirm('confirmCheckout')) {
       const ok = await options.confirm({
         title: '确认结账',
@@ -386,20 +418,29 @@ export function useOrderActions(options: UseOrderActionsOptions) {
 
   async function handleCounterCheckout() {
     if (!order.value) return
+    const reasonText = counterForm.value.reason.trim()
+    if (!reasonText) {
+      options.notifyWarning('请填写修改原因')
+      return
+    }
+    if (!canCounterCheckout.value) {
+      options.notifyWarning('当前不能修改，可能已达 6 轮上限或未轮到你')
+      return
+    }
     countering.value = true
     try {
-      const reasonText = counterForm.value.reason.trim()
       await counterCheckout(order.value.id, {
         content: reasonText,
         consumableAmountYuan: counterForm.value.consumableAmountYuan,
         coin_consumed_m: counterForm.value.coin_consumed_m,
-        // 号主修正只保留「押金赔付扣除」；与 other 同步写入，兼容旧字段语义
         otherAmountYuan: counterForm.value.depositDeductAmountYuan,
         depositDeductAmountYuan: counterForm.value.depositDeductAmountYuan,
         reason: reasonText,
         evidence_urls: linesToList(counterForm.value.evidenceText),
       })
-      options.notifySuccess('结账修正已提交，等待租客确认')
+      options.notifySuccess(
+        isOwner.value ? '结账修正已提交，等待租客处理' : '结账还价已提交，等待号主处理'
+      )
       await loadOrder()
       options.onCounterCheckoutSuccess?.()
     } catch (error) {
@@ -411,20 +452,24 @@ export function useOrderActions(options: UseOrderActionsOptions) {
 
   async function handleAcceptCheckout() {
     if (!order.value) return
+    if (checkoutShortfallCent.value > 0) {
+      options.notifyWarning('押金不足以覆盖打超/赔付，无法自动完结，请修改方案或发起争议由人工处理')
+      return
+    }
     if (needsConfirm('acceptCheckout')) {
       const ok = await options.confirm({
-        title: '同意修正',
-        message: '确定同意号主的结账修正提案吗？同意后订单将完成结算。',
+        title: '同意结账方案',
+        message: '确定同意当前结账方案吗？同意后订单将完成结算。',
       })
       if (!ok) return
     }
     acceptingCheckout.value = true
     try {
       await acceptCheckout(order.value.id)
-      options.notifySuccess('已确认修正结账，订单完成')
+      options.notifySuccess('已确认结账，订单完成')
       await loadOrder()
     } catch (error) {
-      options.notifyError(readError(error, '确认修正失败'))
+      options.notifyError(readError(error, '确认结账失败'))
     } finally {
       acceptingCheckout.value = false
     }
@@ -634,6 +679,11 @@ export function useOrderActions(options: UseOrderActionsOptions) {
     ownerIncomeLabel,
     canOpenDispute,
     canCancelDispute,
+    canCounterCheckout,
+    canAcceptCheckoutProposal,
+    checkoutShortfallCent,
+    checkoutOvershootCent,
+    checkoutRoundLabel,
     isCheckoutDisputeStage,
 
     // Methods