diff --git a/PROJECT_STATE.md b/PROJECT_STATE.md
index 9a40d5f..761449e 100644
--- a/PROJECT_STATE.md
+++ b/PROJECT_STATE.md
@@ -4,16 +4,16 @@
 | --- | --- |
 | 最近更新 | 2026-07-21 |
 | 当前分支 | `feature/huangting` |
-| 当前阶段 | M002 V4 入站、多卡模型、持久化基线、入站写入、查询接口、卡片确认、复核解阻、目录校验、订单详情 V4 总览、DB 目录、Lookup API、前端 lookup 接入、目录管理后台 CP1 前后端、订单列表 V4 继续处理入口 / open count 收口、V4 业务审计查询、停止旧任务双写、Debug EML V4 profile 对齐、Room Information 后端展示模型与前端业务化展示、Rooming List 确认自动 DEF 后端联动、Account + booking type 过滤 Rate Code 文档口径、Payment 附件预览文档口径、Rooming List 事项确认卡文档口径，以及 V4 复核态卡片交互和字段白名单文档口径 |
-| 当前重点 | M002 V4 已停止普通业务入站双写旧 `workflow_reservation_task`，V4 后新业务主线只写 V4 order task / cards / source notification；Debug EML V4 smoke 默认复用实时 AgentBus V4 Open API subject，避免误走历史 Debug V2/V3 profile。开发阶段不维护 V2/V3 旧任务兼容，测试数据可重建，生产迁移策略后续上线前单独设计。`GET /api/reservation/orders` 可返回 V4 下一步订单任务、卡片、动作类型、动作状态、V4 open 数和统一展示字段 `open_work_item_count`；旧 `open_task_count` / `next_processable_task_id` 仅作历史诊断兼容。Room Information 已完成后端稳定展示模型和前端业务化展示：`GET /api/reservation/order-tasks/{orderTaskId}` 在 `display_payload.room_information` 返回 New / Update / Cancel 的 `current_values`、`proposed_values`、`final_values`、`change_summary[]`，前端只消费该展示模型和 `fields[]`，不再从 Agent raw payload、`business_fields` 或 `target_order` 自行推导；Nights、Breakfast 和 Group Booking Status 均以后端派生值为准；确认和复核写入稳定 `confirmed_payload_json.room_information.final_values`，不回写 Agent 原始 `target_order`、Adult、邮件正文或附件 URL。Rooming List 卡确认时已实现 Group 自动置 `DEF`：如同订单存在可更新的已确认 Room Information 快照，后端会覆盖其 `group_booking_status=DEF` 并写 `V4_ROOMING_LIST_AUTO_DEF` 审计；如没有可更新投影，Rooming List 确认仍成功，只写安全审计提示，不临时创建不完整 Room Information。已确认 Rate Code 下一阶段按 Reservation Account + `booking_type`（GROUP / FIT）过滤和校验，不按全酒店 Rate Code 全量展示；已确认 Payment 卡展示付款凭证附件时，`attachment_ids[]` 第一版只读，前端只展示并确认卡片，不增删或替换附件集合，图片在卡片内显示缩略图并点击大图预览，非图片统一文件列表 + 下载，附件外链仍走 SourceMessage 原文权限链路；已确认 Rooming List 任务卡第一版只做事项确认，不做名单解析、附件预览、Excel 生成或 PMS 导入，用户点击“确认卡片”表示已人工处理该 Rooming List 事项；已确认 `REVIEW_REQUIRED` 仍是原业务卡复核态，页面按钮统一叫“确认卡片”，复核态允许编辑当前卡 `fields[]` 白名单内业务字段，问题字段红字提示。后续可继续做测试机 V4 smoke 复测、Rooming List 前端轻量卡展示、Payment 附件预览、Account 范围 Rate Code lookup、真实 PMS / OPERA / OHIP 同步或 SuperAgent 目录供给方案。 |
+| 当前阶段 | M002 V4 入站、多卡模型、持久化基线、入站写入、查询接口、卡片确认、复核解阻、目录校验、订单详情 V4 总览、DB 目录、Lookup API、前端 lookup 接入、目录管理后台 CP1 前后端、订单列表 V4 继续处理入口 / open count 收口、V4 业务审计查询、停止旧任务双写、Debug EML V4 profile 对齐、Room Information 后端展示模型与前端业务化展示、V4 任务详情 smoke 修复、Rooming List 确认自动 DEF 后端联动、Account + booking type 过滤 Rate Code 文档口径、Payment 附件预览文档口径、Rooming List 事项确认卡文档口径，以及 V4 复核态卡片交互和字段白名单文档口径 |
+| 当前重点 | M002 V4 已停止普通业务入站双写旧 `workflow_reservation_task`，V4 后新业务主线只写 V4 order task / cards / source notification；Debug EML V4 smoke 默认复用实时 AgentBus V4 Open API subject，避免误走历史 Debug V2/V3 profile。开发阶段不维护 V2/V3 旧任务兼容，测试数据可重建，生产迁移策略后续上线前单独设计。`GET /api/reservation/orders` 可返回 V4 下一步订单任务、卡片、动作类型、动作状态、V4 open 数和统一展示字段 `open_work_item_count`；旧 `open_task_count` / `next_processable_task_id` 仅作历史诊断兼容。Room Information 已完成后端稳定展示模型和前端业务化展示：`GET /api/reservation/order-tasks/{orderTaskId}` 在 `display_payload.room_information` 返回 New / Update / Cancel 的 `current_values`、`proposed_values`、`final_values`、`change_summary[]`，前端只消费该展示模型和 `fields[]`，不再从 Agent raw payload、`business_fields` 或 `target_order` 自行推导；Nights、Breakfast 和 Group Booking Status 均以后端派生值为准；确认和复核写入稳定 `confirmed_payload_json.room_information.final_values`，不回写 Agent 原始 `target_order`、Adult、邮件正文或附件 URL；接口对前端暴露的 `fields[].write_target` 使用 `confirmed_payload` / `review_resolution.field_overrides` 这类安全语义，不暴露内部列名。V4 任务详情 smoke 修复已完成：页面顺序固定为 Basic Information、业务卡、SourceMessage Display；来源邮件卡位于页面底部，只通过 SourceMessage conversation 接口定位当前触发邮件并默认折叠正文；Basic Information 的展示和确认 payload 不再返回 Agent `target_order`。Rooming List 卡确认时已实现 Group 自动置 `DEF`：如同订单存在可更新的已确认 Room Information 快照，后端会覆盖其 `group_booking_status=DEF` 并写 `V4_ROOMING_LIST_AUTO_DEF` 审计；刷新任务详情时 `display_payload`、`confirmed_payload` 和订单总览均以 DEF 后的确认快照为准；如没有可更新投影，Rooming List 确认仍成功，只写安全审计提示，不临时创建不完整 Room Information。已确认 Rate Code 下一阶段按 Reservation Account + `booking_type`（GROUP / FIT）过滤和校验，不按全酒店 Rate Code 全量展示；已确认 Payment 卡展示付款凭证附件时，`attachment_ids[]` 第一版只读，前端只展示并确认卡片，不增删或替换附件集合，图片在卡片内显示缩略图并点击大图预览，非图片统一文件列表 + 下载，附件外链仍走 SourceMessage 原文权限链路；已确认 Rooming List 任务卡第一版只做事项确认，不做名单解析、附件预览、Excel 生成或 PMS 导入，用户点击“确认卡片”表示已人工处理该 Rooming List 事项；已确认 `REVIEW_REQUIRED` 仍是原业务卡复核态，页面按钮统一叫“确认卡片”，复核态允许编辑当前卡 `fields[]` 白名单内业务字段，问题字段红字提示。后续可继续做测试机 V4 smoke 复测、Rooming List 前端轻量卡展示、Payment 附件预览、Account 范围 Rate Code lookup、真实 PMS / OPERA / OHIP 同步或 SuperAgent 目录供给方案。 |
 
 ## 1. 当前 Checkpoint
 
-- 名称：`M002-V4-rooming-list-confirm-def-backend`
-- 状态：Backend Done，已实现 V4 `ROOMING_LIST` 卡确认后 Group Booking Status 自动置 `DEF` 的后端联动。
-- 目标：普通确认或 `REVIEW_REQUIRED` 复核确认 Rooming List 卡时，如果同订单为 Group 且存在可更新的已确认 Room Information 快照，后端强制覆盖 `group_booking_status=DEF` 并保留审计；Fit 不变更。
-- 边界：本 checkpoint 不改变 Room Information 查询响应结构；不解析名单、不预览附件、不生成 Excel、不导入 PMS、不调用 M010 Rooming List 工具；不推进 Payment 附件预览、Account + booking type Rate Code lookup、真实 PMS / OPERA / OHIP 或 M011 CP4。
-- 联调备注：前端确认 `ROOMING_LIST` 时只需按卡片状态调用普通 confirm 或 `review-resolution`；后端负责自动 DEF 和 `V4_ROOMING_LIST_AUTO_DEF` 审计。没有可更新 Room Information 投影时确认仍成功，不创建不完整 Room Information，只写安全审计提示。
+- 名称：`M002-V4-task-detail-smoke-fixes-frontend`
+- 状态：Frontend Done，已修复测试机 smoke 发现的 V4 任务详情页展示顺序、来源邮件正文和 UPDATE_BOOKING 对比展示问题。
+- 目标：V4 任务详情页展示顺序固定为 Basic Information、业务卡、SourceMessage Display；来源邮件卡位于页面底部，通过 SourceMessage conversation 接口定位当前触发该 order task 的邮件正文，默认折叠并可展开；UPDATE_BOOKING Room Information 明确展示当前值、建议值和最终值。
+- 边界：本 checkpoint 不做 Payment 附件预览、不做 Rate Code lookup、不改后端接口；前端不展示 `ai_payload_json`、raw evidence、附件 URL 或未 sanitize 的 `html_body`。
+- 联调备注：若用户缺少 SourceMessage 原文权限或 conversation 接口失败，来源邮件卡降级展示安全摘要和邮件会话入口；SourceMessage Display 不再渲染后端返回的通用 `fields[]`，避免误透敏感字段。
 
 ## 2. 当前优先级
 
diff --git a/client/src/components/reservation/ReservationV4RoomInformationCard.vue b/client/src/components/reservation/ReservationV4RoomInformationCard.vue
index bf7cbe8..b39233e 100644
--- a/client/src/components/reservation/ReservationV4RoomInformationCard.vue
+++ b/client/src/components/reservation/ReservationV4RoomInformationCard.vue
@@ -36,11 +36,11 @@
       >
         <h3>{{ t('taskV4.roomInformation.currentValues') }}</h3>
         <dl
-          v-if="scalarEntries(currentValues).length"
+          v-if="scalarEntries(currentValues, { hideEditableBreakfast: false }).length"
           class="room-information__grid"
         >
           <template
-            v-for="entry in scalarEntries(currentValues)"
+            v-for="entry in scalarEntries(currentValues, { hideEditableBreakfast: false })"
             :key="entry.key"
           >
             <dt>{{ roomInformationFieldLabel(entry.key) }}</dt>
@@ -78,6 +78,54 @@
         </div>
       </section>
 
+      <section
+        v-if="showProposedValues"
+        class="room-information__panel room-information__panel--proposed"
+      >
+        <h3>{{ t('taskV4.roomInformation.proposedValues') }}</h3>
+        <dl
+          v-if="scalarEntries(proposedValues, { hideEditableBreakfast: false }).length"
+          class="room-information__grid"
+        >
+          <template
+            v-for="entry in scalarEntries(proposedValues, { hideEditableBreakfast: false })"
+            :key="entry.key"
+          >
+            <dt>{{ roomInformationFieldLabel(entry.key) }}</dt>
+            <dd>{{ entry.value }}</dd>
+          </template>
+        </dl>
+        <p
+          v-else-if="!roomItems(proposedValues).length"
+          class="room-information__empty"
+        >
+          {{ t('taskV4.roomInformation.emptyValues') }}
+        </p>
+        <div
+          v-if="roomItems(proposedValues).length"
+          class="room-information__room-items"
+        >
+          <h4>{{ t('taskV4.roomInformation.roomItems') }}</h4>
+          <table>
+            <thead>
+              <tr>
+                <th>{{ t('taskV4.roomInformation.roomTypeCode') }}</th>
+                <th>{{ t('taskV4.roomInformation.roomCount') }}</th>
+              </tr>
+            </thead>
+            <tbody>
+              <tr
+                v-for="(item, index) in roomItems(proposedValues)"
+                :key="index"
+              >
+                <td>{{ formatRoomInformationValue('room_type_code', item.room_type_code, item) }}</td>
+                <td>{{ formatRoomInformationValue('room_count', item.room_count, item) }}</td>
+              </tr>
+            </tbody>
+          </table>
+        </div>
+      </section>
+
       <section class="room-information__panel">
         <h3>{{ t('taskV4.roomInformation.finalValues') }}</h3>
         <div class="room-information__derived">
@@ -210,6 +258,7 @@ const roomInformation = computed<ReservationV4RoomInformationDisplayModel | null
 const eventType = computed(() => roomInformation.value?.event_type ?? props.card.event_type ?? '')
 const bookingType = computed(() => roomInformation.value?.booking_type ?? '')
 const currentValues = computed(() => normalizeValues(roomInformation.value?.current_values))
+const proposedValues = computed(() => normalizeValues(roomInformation.value?.proposed_values))
 const finalValues = computed(() => normalizeValues(roomInformation.value?.final_values))
 const changeSummary = computed(() => roomInformation.value?.change_summary ?? [])
 const visibleChangeSummary = computed(() => changeSummary.value.filter((change) =>
@@ -220,7 +269,12 @@ const visibleFields = computed(() => props.card.fields.filter((field) =>
 ))
 const showChangeSummary = computed(() => eventType.value === 'UPDATE_BOOKING' && visibleChangeSummary.value.length > 0)
 const showCurrentValues = computed(() =>
-  ['CANCEL_BOOKING'].includes(eventType.value) && hasVisibleValues(currentValues.value),
+  ['UPDATE_BOOKING', 'CANCEL_BOOKING'].includes(eventType.value) &&
+    hasVisibleValues(currentValues.value, { hideEditableBreakfast: false }),
+)
+const showProposedValues = computed(() =>
+  eventType.value === 'UPDATE_BOOKING' &&
+    hasVisibleValues(proposedValues.value, { hideEditableBreakfast: false }),
 )
 const showEditableFields = computed(() => eventType.value !== 'CANCEL_BOOKING' && visibleFields.value.length > 0)
 const showReadonlyBreakfast = computed(() =>
@@ -241,11 +295,19 @@ const scalarFieldOrder = [
   'confirmation_number',
 ]
 
-function scalarEntries(values: ReservationV4RoomInformationValues): Array<{ key: string; value: string }> {
+function scalarEntries(
+  values: ReservationV4RoomInformationValues,
+  options: { hideEditableBreakfast?: boolean } = {},
+): Array<{ key: string; value: string }> {
+  const hideEditableBreakfast = options.hideEditableBreakfast ?? true
   return scalarFieldOrder
     .filter((key) => key in values && hasValue(values[key]))
     .filter((key) => key !== 'group_booking_status_label')
-    .filter((key) => key !== 'breakfast_included' || !hasEditableField('/room_information/final_values/breakfast_included'))
+    .filter((key) =>
+      key !== 'breakfast_included' ||
+        !hideEditableBreakfast ||
+        !hasEditableField('/room_information/final_values/breakfast_included'),
+    )
     .map((key) => ({
       key,
       value: formatRoomInformationValue(key, values[key], values),
@@ -279,8 +341,11 @@ function isVisibleRoomInformationChangeField(field: unknown): boolean {
     !key.includes('locator_value')
 }
 
-function hasVisibleValues(values: ReservationV4RoomInformationValues): boolean {
-  return scalarEntries(values).length > 0 || roomItems(values).length > 0
+function hasVisibleValues(
+  values: ReservationV4RoomInformationValues,
+  options: { hideEditableBreakfast?: boolean } = {},
+): boolean {
+  return scalarEntries(values, options).length > 0 || roomItems(values).length > 0
 }
 
 function normalizeValues(value: unknown): ReservationV4RoomInformationValues {
@@ -391,6 +456,11 @@ const roomInformationLabelKeys: Record<string, string> = {
   background: linear-gradient(180deg, var(--th-color-white), var(--th-color-info-bg));
 }
 
+.room-information__panel--proposed {
+  border-color: color-mix(in srgb, var(--th-color-warning) 24%, var(--th-color-slate-200));
+  background: color-mix(in srgb, var(--th-color-warning-bg) 42%, var(--th-color-white));
+}
+
 .room-information__panel--changes ul {
   display: grid;
   gap: 8px;
diff --git a/client/src/components/reservation/ReservationV4SourceMessageCard.vue b/client/src/components/reservation/ReservationV4SourceMessageCard.vue
index bb44d7c..7158746 100644
--- a/client/src/components/reservation/ReservationV4SourceMessageCard.vue
+++ b/client/src/components/reservation/ReservationV4SourceMessageCard.vue
@@ -42,6 +42,51 @@
       <p>{{ sourceExcerpt }}</p>
     </div>
 
+    <div class="source-preview source-body">
+      <h3>{{ t('taskV4.sourceMessage.body') }}</h3>
+      <p
+        v-if="bodyLoading"
+        class="source-body__muted"
+      >
+        {{ t('taskV4.sourceMessage.bodyLoading') }}
+      </p>
+      <p
+        v-else-if="bodyError"
+        class="source-body__muted"
+      >
+        {{ t('taskV4.sourceMessage.bodyLoadFailed') }}
+      </p>
+      <template v-else-if="messageBodyText">
+        <!-- eslint-disable vue/no-v-html -- only backend-sanitized html_body_sanitized is rendered; raw html_body is never used here. -->
+        <div
+          v-if="showExpandedHtmlBody"
+          class="source-body__html"
+          v-html="sanitizedHtmlBody"
+        />
+        <!-- eslint-enable vue/no-v-html -->
+        <p
+          v-else
+          class="source-body__text"
+        >
+          {{ visibleMessageBodyText }}
+        </p>
+        <button
+          v-if="canToggleBody"
+          type="button"
+          class="source-body__toggle"
+          @click="bodyExpanded = !bodyExpanded"
+        >
+          {{ bodyExpanded ? t('taskV4.sourceMessage.collapseBody') : t('taskV4.sourceMessage.showFullBody') }}
+        </button>
+      </template>
+      <p
+        v-else
+        class="source-body__muted"
+      >
+        {{ t('taskV4.sourceMessage.noBody') }}
+      </p>
+    </div>
+
     <div class="source-preview">
       <h3>{{ t('taskV4.sourceMessage.attachments') }}</h3>
       <ul
@@ -65,13 +110,6 @@
       </p>
     </div>
 
-    <ReservationV4TaskCardFieldRenderer
-      v-if="sourceCard?.fields.length"
-      :fields="sourceCard.fields"
-      :model-value="fieldValues"
-      :read-only="true"
-    />
-
     <RouterLink
       v-if="showConversationLink && sourceMessageId"
       class="source-link"
@@ -83,19 +121,19 @@
 </template>
 
 <script setup lang="ts">
-import { computed } from 'vue'
+import { computed, ref, watch } from 'vue'
 import { RouterLink } from 'vue-router'
 import { useI18n } from 'vue-i18n'
 
 import ReservationStatusBadge from '@/components/reservation/ReservationStatusBadge.vue'
-import ReservationV4TaskCardFieldRenderer from '@/components/reservation/ReservationV4TaskCardFieldRenderer.vue'
+import { fetchSourceMessageConversation } from '@/services/reservationService'
 import type {
   ReservationRecord,
+  SourceMessageConversationItem,
   ReservationV4SourceMessageSummary,
   ReservationV4TaskCardResult,
 } from '@/types/reservation'
 import { formatReservationDateTime } from '@/utils/reservationFormat'
-import { buildReservationV4InitialFieldValues } from '@/utils/reservationV4FieldRules'
 
 const props = withDefaults(defineProps<{
   title: string
@@ -107,9 +145,14 @@ const props = withDefaults(defineProps<{
 })
 
 const { t } = useI18n()
+const bodyPreviewLength = 360
+const currentMessage = ref<SourceMessageConversationItem | null>(null)
+const bodyLoading = ref(false)
+const bodyError = ref(false)
+const bodyExpanded = ref(false)
+let bodyRequestSequence = 0
 
 const payload = computed(() => props.sourceCard?.display_payload ?? {})
-const fieldValues = computed(() => buildReservationV4InitialFieldValues(props.sourceCard?.fields ?? []))
 const sourceMessageId = computed(() =>
   props.sourceMessageSummary?.source_message_id ?? readString(payload.value, 'source_message_id'),
 )
@@ -141,11 +184,78 @@ const sourceExcerpt = computed(() =>
     'summary',
   ]) ?? t('taskV4.sourceMessage.noExcerpt'),
 )
-const attachments = computed(() => normalizeAttachments(readFirstDefined(payload.value, [
+const sourcePayloadAttachments = computed(() => normalizeAttachments(readFirstDefined(payload.value, [
   'attachments',
   'uploaded_media',
   'file_references',
 ])))
+const currentMessageAttachments = computed(() => normalizeAttachments([
+  ...(currentMessage.value?.attachments ?? []),
+  ...(currentMessage.value?.inline_images ?? []),
+]))
+const attachments = computed(() =>
+  sourcePayloadAttachments.value.length ? sourcePayloadAttachments.value : currentMessageAttachments.value,
+)
+const sanitizedHtmlBody = computed(() => {
+  const message = currentMessage.value
+  const htmlBody = message?.html_body_sanitized?.trim()
+  if (!htmlBody || (message?.html_render_mode && message.html_render_mode !== 'SANITIZED_HTML')) {
+    return ''
+  }
+  return htmlBody
+})
+const messageBodyText = computed(() => {
+  if (sanitizedHtmlBody.value) {
+    return htmlToText(sanitizedHtmlBody.value)
+  }
+  return compactBodyText(currentMessage.value?.text_body ?? '')
+})
+const canToggleBody = computed(() => messageBodyText.value.length > bodyPreviewLength)
+const visibleMessageBodyText = computed(() => {
+  if (!canToggleBody.value || bodyExpanded.value) {
+    return messageBodyText.value
+  }
+  return `${messageBodyText.value.slice(0, bodyPreviewLength).trimEnd()}...`
+})
+const showExpandedHtmlBody = computed(() =>
+  bodyExpanded.value && Boolean(sanitizedHtmlBody.value),
+)
+
+watch(sourceMessageId, (nextSourceMessageId) => {
+  void loadCurrentSourceMessage(nextSourceMessageId)
+}, { immediate: true })
+
+async function loadCurrentSourceMessage(nextSourceMessageId: string | null) {
+  bodyRequestSequence += 1
+  const requestSequence = bodyRequestSequence
+  currentMessage.value = null
+  bodyError.value = false
+  bodyExpanded.value = false
+
+  if (!nextSourceMessageId) {
+    bodyLoading.value = false
+    return
+  }
+
+  bodyLoading.value = true
+  try {
+    const conversation = await fetchSourceMessageConversation(nextSourceMessageId)
+    if (requestSequence !== bodyRequestSequence) {
+      return
+    }
+    currentMessage.value = conversation.messages.find((message) =>
+      String(message.id) === String(nextSourceMessageId),
+    ) ?? null
+  } catch {
+    if (requestSequence === bodyRequestSequence) {
+      bodyError.value = true
+    }
+  } finally {
+    if (requestSequence === bodyRequestSequence) {
+      bodyLoading.value = false
+    }
+  }
+}
 
 interface AttachmentSummary {
   key: string
@@ -175,10 +285,10 @@ function normalizeAttachments(value: unknown): AttachmentSummary[] {
 function toAttachmentSummary(value: unknown, index: number): AttachmentSummary {
   const record = readRecord(value)
   const name = record
-    ? safeAttachmentName(readFirstString(record, ['name', 'file_name', 'filename', 'display_name', 'title']))
+    ? safeAttachmentName(readFirstString(record, ['name', 'file_name', 'fileName', 'filename', 'display_name', 'title']))
     : safeAttachmentName(String(value))
-  const type = record ? readFirstString(record, ['content_type', 'mime_type', 'media_type', 'file_type']) : null
-  const size = record ? readNumber(record, 'size_bytes') ?? readNumber(record, 'size') : null
+  const type = record ? readFirstString(record, ['content_type', 'contentType', 'mime_type', 'media_type', 'mediaType', 'file_type']) : null
+  const size = record ? readNumber(record, 'size_bytes') ?? readNumber(record, 'sizeBytes') ?? readNumber(record, 'size') : null
   return {
     key: `${name}-${index}`,
     name,
@@ -261,6 +371,19 @@ function safeAttachmentName(value: string | null): string {
 function isUnsafeAttachmentText(value: string): boolean {
   return /^(https?:\/\/|oss:\/\/|s3:\/\/)/i.test(value.trim())
 }
+
+function htmlToText(value: string): string {
+  if (typeof document !== 'undefined') {
+    const element = document.createElement('div')
+    element.innerHTML = value
+    return compactBodyText(element.textContent ?? '')
+  }
+  return compactBodyText(value.replace(/<[^>]*>/g, ' '))
+}
+
+function compactBodyText(value: string): string {
+  return value.replace(/\s+/g, ' ').trim()
+}
 </script>
 
 <style scoped>
@@ -307,6 +430,34 @@ function isUnsafeAttachmentText(value: string): boolean {
   margin: 0;
 }
 
+.source-body__text,
+.source-body__html {
+  max-width: 100%;
+  color: var(--th-color-slate-900);
+  font-size: 13px;
+  line-height: 1.65;
+  overflow-wrap: anywhere;
+}
+
+.source-body__html :deep(*) {
+  max-width: 100%;
+}
+
+.source-body__muted {
+  color: var(--th-color-slate-500);
+}
+
+.source-body__toggle {
+  justify-self: start;
+  border: 0;
+  background: transparent;
+  color: var(--th-color-blue-600);
+  cursor: pointer;
+  font-size: 13px;
+  font-weight: 900;
+  padding: 0;
+}
+
 .attachment-list {
   display: grid;
   gap: 8px;
diff --git a/client/src/i18n/locales/en-US.ts b/client/src/i18n/locales/en-US.ts
index 35e28dc..40c1f31 100644
--- a/client/src/i18n/locales/en-US.ts
+++ b/client/src/i18n/locales/en-US.ts
@@ -625,6 +625,12 @@ export default {
       conversationCount: 'Conversation messages',
       attachments: 'Attachments',
       excerpt: 'Email excerpt',
+      body: 'Current email body',
+      bodyLoading: 'Loading current email body...',
+      bodyLoadFailed: 'Current email body cannot be loaded right now. Open the email conversation to view it.',
+      noBody: 'No current email body.',
+      showFullBody: 'Show full body',
+      collapseBody: 'Collapse body',
       noExcerpt: 'No email excerpt',
       noAttachments: 'No attachments',
     },
diff --git a/client/src/i18n/locales/th-TH.ts b/client/src/i18n/locales/th-TH.ts
index 35fccd6..1923046 100644
--- a/client/src/i18n/locales/th-TH.ts
+++ b/client/src/i18n/locales/th-TH.ts
@@ -625,6 +625,12 @@ export default {
       conversationCount: 'จำนวนอีเมลในเธรด',
       attachments: 'ไฟล์แนบ',
       excerpt: 'ข้อความบางส่วนของอีเมล',
+      body: 'เนื้อหาอีเมลปัจจุบัน',
+      bodyLoading: 'กำลังโหลดเนื้อหาอีเมลปัจจุบัน...',
+      bodyLoadFailed: 'ยังโหลดเนื้อหาอีเมลปัจจุบันไม่ได้ โปรดเปิดเธรดอีเมลเพื่อดู',
+      noBody: 'ไม่มีเนื้อหาอีเมลปัจจุบัน',
+      showFullBody: 'แสดงทั้งหมด',
+      collapseBody: 'ย่อเนื้อหา',
       noExcerpt: 'ไม่มีข้อความบางส่วน',
       noAttachments: 'ไม่มีไฟล์แนบ',
     },
diff --git a/client/src/i18n/locales/zh-CN.ts b/client/src/i18n/locales/zh-CN.ts
index de49f58..c05cb24 100644
--- a/client/src/i18n/locales/zh-CN.ts
+++ b/client/src/i18n/locales/zh-CN.ts
@@ -625,6 +625,12 @@ export default {
       conversationCount: '会话邮件数',
       attachments: '附件',
       excerpt: '邮件片段',
+      body: '当前邮件正文',
+      bodyLoading: '正在加载当前邮件正文...',
+      bodyLoadFailed: '当前邮件正文暂时无法加载，可进入邮件会话查看。',
+      noBody: '暂无当前邮件正文。',
+      showFullBody: '展开全文',
+      collapseBody: '收起正文',
       noExcerpt: '暂无邮件片段',
       noAttachments: '无附件',
     },
diff --git a/client/src/tests/reservationV4Views.spec.ts b/client/src/tests/reservationV4Views.spec.ts
index cac08c7..b31a902 100644
--- a/client/src/tests/reservationV4Views.spec.ts
+++ b/client/src/tests/reservationV4Views.spec.ts
@@ -11,6 +11,7 @@ import type {
   ReservationV4OrderTaskDetailResult,
   ReservationV4SourceNotificationDetailResult,
   ReservationV4TaskCardResult,
+  SourceMessageConversationResult,
 } from '@/types/reservation'
 import ReservationV4OrderTaskDetailView from '@/views/reservation/ReservationV4OrderTaskDetailView.vue'
 import ReservationV4SourceNotificationDetailView from '@/views/reservation/ReservationV4SourceNotificationDetailView.vue'
@@ -27,6 +28,7 @@ vi.mock('@/services/reservationService', async (importOriginal) => {
     fetchReservationV4RateCodeLookups: vi.fn(),
     fetchReservationV4RoomTypeLookups: vi.fn(),
     fetchReservationV4SourceNotificationDetail: vi.fn(),
+    fetchSourceMessageConversation: vi.fn(),
     resolveReservationV4OrderTaskCardReview: vi.fn(),
   }
 })
@@ -43,7 +45,9 @@ describe('reservation V4 pages', () => {
     vi.mocked(service.fetchReservationV4RateCodeLookups).mockReset()
     vi.mocked(service.fetchReservationV4RoomTypeLookups).mockReset()
     vi.mocked(service.fetchReservationV4SourceNotificationDetail).mockReset()
+    vi.mocked(service.fetchSourceMessageConversation).mockReset()
     vi.mocked(service.resolveReservationV4OrderTaskCardReview).mockReset()
+    vi.mocked(service.fetchSourceMessageConversation).mockResolvedValue(createSourceMessageConversationResult())
     mockCatalogLookups()
   })
 
@@ -150,6 +154,139 @@ describe('reservation V4 pages', () => {
     expect(wrapper.text()).not.toContain('oss://bucket')
   })
 
+  it('renders V4 source message display at the bottom with only the current email body collapsed', async () => {
+    const detail = createOrderTaskDetail()
+    detail.source_message_card!.fields = [
+      createField('/source_message/ai_payload_json', {
+        display_name: 'AI payload',
+        value: 'AI_PAYLOAD_SHOULD_NOT_RENDER',
+      }),
+      createField('/source_message/raw_evidence', {
+        display_name: 'Raw evidence',
+        value: 'RAW_EVIDENCE_SHOULD_NOT_RENDER',
+      }),
+      createField('/source_message/attachment_url', {
+        display_name: 'Attachment URL',
+        value: 'https://oss.example/private/source-field.pdf',
+      }),
+    ]
+    const currentBody = `Current trigger email body opening. ${'Current booking detail. '.repeat(24)}CURRENT_BODY_TAIL`
+    vi.mocked(service.fetchReservationV4OrderTaskDetail).mockResolvedValue(detail)
+    vi.mocked(service.fetchSourceMessageConversation).mockResolvedValue(createSourceMessageConversationResult({
+      sourceMessageId: '30001',
+      currentBody,
+    }))
+
+    const wrapper = await mountWithPlugins(
+      ReservationV4OrderTaskDetailView,
+      '/reservation/order-tasks/9001',
+    )
+    await flushPromises()
+
+    expect(service.fetchSourceMessageConversation).toHaveBeenCalledWith('30001')
+    const pageText = wrapper.text()
+    const basicIndex = pageText.indexOf(zhCN.taskV4.basicInformationCard)
+    const businessIndex = pageText.indexOf(zhCN.taskV4.businessCards)
+    const sourceIndex = pageText.indexOf(zhCN.taskV4.sourceMessageCard)
+    expect(basicIndex).toBeGreaterThanOrEqual(0)
+    expect(businessIndex).toBeGreaterThan(basicIndex)
+    expect(sourceIndex).toBeGreaterThan(businessIndex)
+    const sections = wrapper.findAll('.th-section')
+    expect(sections[sections.length - 1]?.text()).toContain(zhCN.taskV4.sourceMessageCard)
+    expect(pageText).toContain('Current trigger email body opening.')
+    expect(pageText).not.toContain('OLDER_MESSAGE_BODY')
+    expect(pageText).not.toContain('REPLY_MESSAGE_BODY')
+    expect(pageText).not.toContain('CURRENT_BODY_TAIL')
+    expect(pageText).not.toContain('AI_PAYLOAD_SHOULD_NOT_RENDER')
+    expect(pageText).not.toContain('RAW_EVIDENCE_SHOULD_NOT_RENDER')
+    expect(pageText).not.toContain('https://oss.example/private/source-field.pdf')
+
+    const expandButton = wrapper
+      .findAll('button')
+      .find((button) => button.text().includes(zhCN.taskV4.sourceMessage.showFullBody))
+    expect(expandButton).toBeTruthy()
+    await expandButton!.trigger('click')
+    await flushPromises()
+
+    expect(wrapper.text()).toContain('CURRENT_BODY_TAIL')
+    expect(wrapper.text()).toContain(zhCN.taskV4.sourceMessage.collapseBody)
+  })
+
+  it('falls back to source summary when current source message body cannot be loaded', async () => {
+    const detail = createOrderTaskDetail()
+    vi.mocked(service.fetchReservationV4OrderTaskDetail).mockResolvedValue(detail)
+    vi.mocked(service.fetchSourceMessageConversation).mockRejectedValue(new ApiError('Forbidden', 403, {
+      code: 'SOURCE_MESSAGE_ORIGINAL_READ_FORBIDDEN',
+      message: 'Forbidden',
+    }))
+
+    const wrapper = await mountWithPlugins(
+      ReservationV4OrderTaskDetailView,
+      '/reservation/order-tasks/9001',
+    )
+    await flushPromises()
+
+    expect(wrapper.text()).toContain('Please book one twin room.')
+    expect(wrapper.text()).toContain(zhCN.taskV4.sourceMessage.bodyLoadFailed)
+    expect(wrapper.text()).toContain(zhCN.task.viewConversation)
+  })
+
+  it('renders only sanitized source message html and never raw html body', async () => {
+    const detail = createOrderTaskDetail()
+    const sanitizedHtml = `<p>Sanitized current email opening. ${'Sanitized detail. '.repeat(24)}SANITIZED_HTML_TAIL</p>`
+    vi.mocked(service.fetchReservationV4OrderTaskDetail).mockResolvedValue(detail)
+    vi.mocked(service.fetchSourceMessageConversation).mockResolvedValue(createSourceMessageConversationResult({
+      sourceMessageId: '30001',
+      currentBody: '',
+      sanitizedHtml,
+      rawHtml: '<script>RAW_HTML_SHOULD_NOT_RENDER</script>',
+      htmlRenderMode: 'SANITIZED_HTML',
+    }))
+
+    const wrapper = await mountWithPlugins(
+      ReservationV4OrderTaskDetailView,
+      '/reservation/order-tasks/9001',
+    )
+    await flushPromises()
+
+    expect(wrapper.text()).toContain('Sanitized current email opening.')
+    expect(wrapper.text()).not.toContain('SANITIZED_HTML_TAIL')
+    expect(wrapper.text()).not.toContain('RAW_HTML_SHOULD_NOT_RENDER')
+
+    const expandButton = wrapper
+      .findAll('button')
+      .find((button) => button.text().includes(zhCN.taskV4.sourceMessage.showFullBody))
+    expect(expandButton).toBeTruthy()
+    await expandButton!.trigger('click')
+    await flushPromises()
+
+    expect(wrapper.text()).toContain('SANITIZED_HTML_TAIL')
+    expect(wrapper.html()).toContain('<p>Sanitized current email opening.')
+    expect(wrapper.html()).not.toContain('RAW_HTML_SHOULD_NOT_RENDER')
+  })
+
+  it('does not render sanitized html when backend marks the email body as text only', async () => {
+    const detail = createOrderTaskDetail()
+    vi.mocked(service.fetchReservationV4OrderTaskDetail).mockResolvedValue(detail)
+    vi.mocked(service.fetchSourceMessageConversation).mockResolvedValue(createSourceMessageConversationResult({
+      sourceMessageId: '30001',
+      currentBody: 'Plain text fallback body.',
+      sanitizedHtml: '<p>SANITIZED_HTML_SHOULD_NOT_RENDER</p>',
+      rawHtml: '<p>RAW_HTML_SHOULD_NOT_RENDER</p>',
+      htmlRenderMode: 'TEXT_ONLY',
+    }))
+
+    const wrapper = await mountWithPlugins(
+      ReservationV4OrderTaskDetailView,
+      '/reservation/order-tasks/9001',
+    )
+    await flushPromises()
+
+    expect(wrapper.text()).toContain('Plain text fallback body.')
+    expect(wrapper.text()).not.toContain('SANITIZED_HTML_SHOULD_NOT_RENDER')
+    expect(wrapper.text()).not.toContain('RAW_HTML_SHOULD_NOT_RENDER')
+  })
+
   it('renders New Booking Room Information as a business form and confirms stable final values', async () => {
     const detail = createOrderTaskDetail({
       businessEventType: 'NEW_BOOKING',
@@ -393,6 +530,8 @@ describe('reservation V4 pages', () => {
 
     const roomCard = wrapper.find('[data-testid="room-information-card"]')
     expect(roomCard.text()).toContain(zhCN.taskV4.roomInformation.changeSummary)
+    expect(roomCard.text()).toContain(zhCN.taskV4.roomInformation.currentValues)
+    expect(roomCard.text()).toContain(zhCN.taskV4.roomInformation.proposedValues)
     expect(roomCard.text()).toContain('2026-07-26')
     expect(roomCard.text()).toContain('2026-07-27')
     expect(roomCard.text()).toContain('3')
@@ -986,6 +1125,81 @@ function createOrderTaskDetail(options: {
   }
 }
 
+function createSourceMessageConversationResult(options: {
+  sourceMessageId?: string
+  currentBody?: string
+  sanitizedHtml?: string | null
+  rawHtml?: string | null
+  htmlRenderMode?: SourceMessageConversationResult['messages'][number]['html_render_mode']
+} = {}): SourceMessageConversationResult {
+  const sourceMessageId = options.sourceMessageId ?? '30001'
+  const currentBody = options.currentBody ?? 'Current trigger email body.'
+  return {
+    conversation: {
+      hotel_id: 'HOTEL-TEST',
+      channel: 'EMAIL',
+      external_conversation_id: 'thread-1',
+      subject: 'Booking Request',
+      message_count: 3,
+      first_received_at: '2026-07-08T02:00:00Z',
+      last_received_at: '2026-07-08T04:00:00Z',
+    },
+    messages: [
+      createConversationMessage({
+        id: '29999',
+        text_body: 'OLDER_MESSAGE_BODY',
+        received_at: '2026-07-08T02:00:00Z',
+      }),
+      createConversationMessage({
+        id: sourceMessageId,
+        text_body: currentBody,
+        html_body: options.rawHtml ?? null,
+        html_body_sanitized: options.sanitizedHtml ?? null,
+        html_render_mode: options.htmlRenderMode,
+        received_at: '2026-07-08T03:00:00Z',
+        attachments: [
+          {
+            mediaType: 'ATTACHMENT',
+            fileName: 'current-message.pdf',
+            contentType: 'application/pdf',
+            sizeBytes: 2048,
+            externalUrl: 'https://oss.example/private/current-message.pdf',
+            externalMediaId: 'media-current',
+          },
+        ],
+      }),
+      createConversationMessage({
+        id: '30002',
+        text_body: 'REPLY_MESSAGE_BODY',
+        received_at: '2026-07-08T04:00:00Z',
+      }),
+    ],
+  }
+}
+
+function createConversationMessage(
+  overrides: Partial<SourceMessageConversationResult['messages'][number]> & { id: string },
+): SourceMessageConversationResult['messages'][number] {
+  return {
+    id: overrides.id,
+    external_message_id: overrides.external_message_id ?? `external-${overrides.id}`,
+    external_conversation_id: overrides.external_conversation_id ?? 'thread-1',
+    sender_summary: overrides.sender_summary ?? 'guest@example.test',
+    subject: overrides.subject ?? 'Booking Request',
+    received_at: overrides.received_at ?? '2026-07-08T03:00:00Z',
+    source_sent_at: overrides.source_sent_at ?? null,
+    text_body: overrides.text_body ?? null,
+    html_body: overrides.html_body ?? null,
+    html_body_sanitized: overrides.html_body_sanitized ?? null,
+    html_sanitize_required: overrides.html_sanitize_required ?? false,
+    html_render_mode: overrides.html_render_mode ?? (overrides.html_body_sanitized ? 'SANITIZED_HTML' : 'TEXT_ONLY'),
+    inline_images: overrides.inline_images ?? [],
+    attachments: overrides.attachments ?? [],
+    related_orders: overrides.related_orders ?? [],
+    related_tasks: overrides.related_tasks ?? [],
+  }
+}
+
 function createRoomInformationDisplayPayload(overrides: {
   event_type?: string
   booking_type?: string
diff --git a/client/src/views/reservation/ReservationV4OrderTaskDetailView.vue b/client/src/views/reservation/ReservationV4OrderTaskDetailView.vue
index 7f65530..0decd87 100644
--- a/client/src/views/reservation/ReservationV4OrderTaskDetailView.vue
+++ b/client/src/views/reservation/ReservationV4OrderTaskDetailView.vue
@@ -78,12 +78,6 @@
         </div>
       </section>
 
-      <ReservationV4SourceMessageCard
-        :title="t('taskV4.sourceMessageCard')"
-        :source-message-summary="detail.source_message_summary"
-        :source-card="detail.source_message_card"
-      />
-
       <TaskCardSection
         v-if="detail.basic_information_card"
         :card="detail.basic_information_card"
@@ -177,6 +171,12 @@
           </article>
         </div>
       </section>
+
+      <ReservationV4SourceMessageCard
+        :title="t('taskV4.sourceMessageCard')"
+        :source-message-summary="detail.source_message_summary"
+        :source-card="detail.source_message_card"
+      />
     </template>
   </div>
 </template>