优化: 脉络卡归属置顶与源会话跳转

- 当前会话归属项目组置顶,focused 标记高亮
- source_ref 解析出可跳转会话 id,消息级引用反查补全
- 条目相对时间/空态引导/标题点击跳源,失败静默

src/components/ai/ContextBriefsCard.vue

@@ -1,6 +1,7 @@
 <template>
   <!-- 脉络卡:同项目近期决策摘要,纯读侧。用户点「带入上下文」向输入框投递追加文本,
-       由用户编辑后自行发送——注入决策权在用户,不触碰 L3 召回铁律。 -->
+       由用户编辑后自行发送——注入决策权在用户,不触碰 L3 召回铁律。
+       有源会话的条目标题可点跳回原文,空源或跳转失败静默不打断阅读。 -->
   <div class="ctx-briefs">
     <button
       class="ctx-briefs-toggle"
@@ -19,9 +20,19 @@
       <div v-if="loading" class="ctx-briefs-empty">{{ t('aiChat.contextBriefsLoading') }}</div>
       <div v-else-if="groups.length === 0" class="ctx-briefs-empty">{{ t('aiChat.contextBriefsEmpty') }}</div>
       <div v-for="g in groups" v-else :key="g.source_project" class="ctx-briefs-group">
-        <div class="ctx-briefs-project">{{ g.source_project }}</div>
+        <div class="ctx-briefs-project">
+          <span v-if="g.focused" class="ctx-briefs-focus-dot" />{{ g.source_project }}
+        </div>
         <div v-for="b in g.briefs" :key="g.source_project + b.title" class="ctx-briefs-item">
-          <div class="ctx-briefs-item-title">{{ b.title }}</div>
+          <div class="ctx-briefs-item-head">
+            <button
+              v-if="b.source_conv"
+              class="ctx-briefs-item-title ctx-briefs-item-link"
+              @click="openSource(b)"
+            >{{ b.title }}</button>
+            <span v-else class="ctx-briefs-item-title">{{ b.title }}</span>
+            <span class="ctx-briefs-item-time">{{ formatRelative(b.updated_at) }}</span>
+          </div>
           <div class="ctx-briefs-item-summary">{{ b.summary }}</div>
           <button
             class="ctx-briefs-bring"
@@ -35,26 +46,32 @@
 </template>
 
 <script setup lang="ts">
-import { ref, computed } from 'vue'
+import { ref, computed, watch } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { aiApi } from '../../api/ai'
 import { useAiStore } from '../../stores/ai'
 import { pushConvDraftAppend } from '../../composables/ai/aiShared'
+import { useAiConversations } from '../../composables/ai/useAiConversations'
+import { formatRelative } from '../../utils/time'
 
 interface ContextBrief {
   title: string
   summary: string
   source_ref: string | null
+  source_conv: string | null
   source_project: string | null
   reuse_count: number
+  updated_at: string
 }
 interface ProjectBriefs {
   source_project: string
+  focused?: boolean
   briefs: ContextBrief[]
 }
 
 const { t } = useI18n()
 const store = useAiStore()
+const { openConversation } = useAiConversations()
 
 const expanded = ref(false)
 const loading = ref(false)
@@ -62,17 +79,39 @@ const groups = ref<ProjectBriefs[]>([])
 
 const totalBriefs = computed(() => groups.value.reduce((n, g) => n + g.briefs.length, 0))
 
+/** 拉取脉络,按当前会话标注聚焦分组;会话已切走时丢弃过期响应(防旧 focused 污染新列表) */
+async function load() {
+  const convId = store.state.activeConversationId ?? undefined
+  loading.value = true
+  try {
+    const result = await aiApi.listContextBriefs(undefined, convId)
+    if ((store.state.activeConversationId ?? undefined) === convId) groups.value = result
+  } catch {
+    if ((store.state.activeConversationId ?? undefined) === convId) groups.value = []
+  } finally {
+    loading.value = false
+  }
+}
+
 async function toggle() {
   expanded.value = !expanded.value
-  if (expanded.value && groups.value.length === 0) {
-    loading.value = true
-    try {
-      groups.value = await aiApi.listContextBriefs()
-    } catch {
-      groups.value = []
-    } finally {
-      loading.value = false
-    }
+  if (expanded.value && groups.value.length === 0) await load()
+}
+
+/** 切会话重新拉取(focused 跟随当前会话);收起态只清缓存,保持按需加载 */
+watch(() => store.state.activeConversationId, () => {
+  groups.value = []
+  if (expanded.value) void load()
+})
+
+/** 跳回摘要来源会话(source_conv 由后端自 source_ref 解析,消息级引用已反查);
+ *  源为空或已删除(not_found)一律静默,不加 toast */
+async function openSource(b: ContextBrief) {
+  if (!b.source_conv) return
+  try {
+    await openConversation(b.source_conv)
+  } catch {
+    // 静默:跳转失败不打断阅读
   }
 }
 
@@ -124,14 +163,45 @@ function bringIn(g: ProjectBriefs, b: ContextBrief) {
   color: var(--text-primary, #333);
   padding: 5px 2px 2px;
 }
+.ctx-briefs-focus-dot {
+  display: inline-block;
+  width: 5px;
+  height: 5px;
+  margin-right: 4px;
+  border-radius: 50%;
+  background: var(--accent, #4080ff);
+  vertical-align: 2px;
+}
 .ctx-briefs-item {
   padding: 4px 2px;
   border-top: 1px dashed var(--border, #eee);
 }
+.ctx-briefs-item-head {
+  display: flex;
+  align-items: baseline;
+  gap: 6px;
+}
 .ctx-briefs-item-title {
   font-weight: 500;
   color: var(--text-primary, #333);
 }
+.ctx-briefs-item-link {
+  padding: 0;
+  border: none;
+  background: none;
+  font: inherit;
+  text-align: left;
+  cursor: pointer;
+}
+.ctx-briefs-item-link:hover {
+  color: var(--accent, #4080ff);
+}
+.ctx-briefs-item-time {
+  margin-left: auto;
+  flex-shrink: 0;
+  font-size: 11px;
+  color: var(--text-tertiary, #999);
+}
 .ctx-briefs-item-summary {
   color: var(--text-secondary, #666);
   margin: 2px 0;