feat: 添加项目置顶功能

在仪表盘中添加置顶项目功能，包括：
- 新增置顶项目展示区域
- 为AI推荐项目添加置顶/取消置顶操作
- 后端接口支持置顶状态管理

frontend/src/components/Dashboard-AI.vue

@@ -7,6 +7,55 @@
         获取 AI 推荐
       </el-button>
     </div>
+    <el-row :gutter="20">
+      <el-col :span="24">
+        <el-card class="box-card" shadow="hover">
+          <template #header>
+            <div class="card-header">
+              <span>Pined</span>
+              <el-tag type="danger">{{ pinnedBids.length }} 个置顶</el-tag>
+            </div>
+          </template>
+          <div v-if="pinnedLoading" style="text-align: center; padding: 40px;">
+            <el-icon class="is-loading" :size="30"><Loading /></el-icon>
+            <p style="margin-top: 10px; color: #909399;">加载中...</p>
+          </div>
+          <div v-else-if="pinnedBids.length === 0" style="text-align: center; padding: 40px; color: #909399;">
+            <el-icon :size="40"><InfoFilled /></el-icon>
+            <p style="margin-top: 10px;">暂无置顶项目</p>
+          </div>
+          <div v-else>
+            <el-table :data="pinnedBids" style="width: 100%" size="small">
+              <el-table-column label="Pin" width="60" align="center">
+                <template #default="scope">
+                  <el-icon
+                    :style="{
+                      color: '#f56c6c',
+                      cursor: 'pointer',
+                      fontSize: '18px'
+                    }"
+                    @click="togglePinnedPin(scope.row)"
+                  >
+                    <Paperclip />
+                  </el-icon>
+                </template>
+              </el-table-column>
+              <el-table-column prop="title" label="项目名称">
+                <template #default="scope">
+                  <a :href="scope.row.url" target="_blank">{{ scope.row.title }}</a>
+                </template>
+              </el-table-column>
+              <el-table-column prop="source" label="来源" width="200" />
+              <el-table-column prop="publishDate" label="发布日期" width="180">
+                <template #default="scope">
+                  {{ formatDate(scope.row.publishDate) }}
+                </template>
+              </el-table-column>
+            </el-table>
+          </div>
+        </el-card>
+      </el-col>
+    </el-row>
     <el-row :gutter="20">
       <el-col :span="24">
         <el-card class="box-card" shadow="hover">
@@ -27,6 +76,20 @@
           </div>
           <div v-else>
             <el-table :data="aiRecommendations" style="width: 100%" size="small">
+              <el-table-column label="Pin" width="60" align="center">
+                <template #default="scope">
+                  <el-icon
+                    :style="{
+                      color: scope.row.pin ? '#f56c6c' : '#909399',
+                      cursor: 'pointer',
+                      fontSize: '18px'
+                    }"
+                    @click="togglePin(scope.row)"
+                  >
+                    <Paperclip />
+                  </el-icon>
+                </template>
+              </el-table-column>
               <el-table-column prop="title" label="项目名称">
                 <template #default="scope">
                   <a :href="scope.row.url" target="_blank">{{ scope.row.title }}</a>
@@ -114,7 +177,7 @@
 import { ref, watch } from 'vue'
 import axios from 'axios'
 import { ElMessage } from 'element-plus'
-import { MagicStick, Loading, InfoFilled, List, ArrowDown } from '@element-plus/icons-vue'
+import { MagicStick, Loading, InfoFilled, List, ArrowDown, Paperclip } from '@element-plus/icons-vue'
 
 
 interface AIRecommendation {
@@ -123,6 +186,7 @@ interface AIRecommendation {
   source: string
   confidence: number
   publishDate?: string
+  pin?: boolean
 }
 
 interface Props {
@@ -137,6 +201,8 @@ const dateRange = ref<[string, string] | null>(null)
 const showAllBids = ref(false)
 const bidsLoading = ref(false)
 const bidsByDateRange = ref<any[]>([])
+const pinnedBids = ref<any[]>([])
+const pinnedLoading = ref(false)
 
 // 从 localStorage 加载保存的日期范围
 const loadSavedDateRange = () => {
@@ -159,15 +225,39 @@ watch(dateRange, (newDateRange) => {
 const loadLatestRecommendations = async () => {
   try {
     const response = await axios.get('/api/ai/latest-recommendations')
-    aiRecommendations.value = response.data
+    const recommendations = response.data
+    
+    // 获取所有置顶的项目
+    const pinnedResponse = await axios.get('/api/bids/pinned')
+    const pinnedTitles = new Set(pinnedResponse.data.map((b: any) => b.title))
+    
+    // 更新每个推荐项目的 pin 状态
+    aiRecommendations.value = recommendations.map((rec: any) => ({
+      ...rec,
+      pin: pinnedTitles.has(rec.title)
+    }))
   } catch (error) {
     console.error('Failed to load latest recommendations:', error)
   }
 }
 
-// 初始化时加载保存的日期范围和最新的 AI 推荐
+// 加载置顶项目
+const loadPinnedBids = async () => {
+  pinnedLoading.value = true
+  try {
+    const response = await axios.get('/api/bids/pinned')
+    pinnedBids.value = response.data
+  } catch (error) {
+    console.error('Failed to load pinned bids:', error)
+  } finally {
+    pinnedLoading.value = false
+  }
+}
+
+// 初始化时加载保存的日期范围、最新的 AI 推荐和置顶项目
 loadSavedDateRange()
 loadLatestRecommendations()
+loadPinnedBids()
 
 // 设置日期范围为最近3天
 const setLast3Days = () => {
@@ -225,7 +315,8 @@ const fetchAIRecommendations = async () => {
         url: bid?.url || '',
         source: bid?.source || '',
         confidence: rec.confidence,
-        publishDate: bid?.publishDate
+        publishDate: bid?.publishDate,
+        pin: bid?.pin || false
       }
     })
 
@@ -299,6 +390,53 @@ const getConfidenceType = (confidence: number) => {
   if (confidence >= 70) return 'warning'
   return 'info'
 }
+
+// 切换 AI 推荐项目的 Pin 状态
+const togglePin = async (item: AIRecommendation) => {
+  try {
+    const newPinStatus = !item.pin
+    await axios.patch(`/api/bids/${encodeURIComponent(item.title)}/pin`, { pin: newPinStatus })
+    item.pin = newPinStatus
+    if (newPinStatus) {
+      // 添加到置顶列表
+      pinnedBids.value.unshift({
+        title: item.title,
+        url: item.url,
+        source: item.source,
+        publishDate: item.publishDate,
+        pin: true
+      })
+    } else {
+      // 从置顶列表移除
+      const index = pinnedBids.value.findIndex(b => b.title === item.title)
+      if (index !== -1) {
+        pinnedBids.value.splice(index, 1)
+      }
+    }
+    ElMessage.success(newPinStatus ? '已置顶' : '已取消置顶')
+  } catch (error) {
+    ElMessage.error('操作失败')
+  }
+}
+
+// 切换置顶列表的 Pin 状态
+const togglePinnedPin = async (item: any) => {
+  try {
+    await axios.patch(`/api/bids/${encodeURIComponent(item.title)}/pin`, { pin: false })
+    const index = pinnedBids.value.findIndex(b => b.title === item.title)
+    if (index !== -1) {
+      pinnedBids.value.splice(index, 1)
+    }
+    // 同时更新 AI 推荐列表中的状态
+    const aiItem = aiRecommendations.value.find(r => r.title === item.title)
+    if (aiItem) {
+      aiItem.pin = false
+    }
+    ElMessage.success('已取消置顶')
+  } catch (error) {
+    ElMessage.error('操作失败')
+  }
+}
 </script>
 
 <style scoped>