feat(electron): 添加Electron桌面应用支持

- 新增Electron主进程、预加载脚本和构建配置
- 修改前端配置以支持Electron打包
- 更新项目文档和依赖
- 重构API调用使用统一axios实例

frontend/src/components/Dashboard-AI.vue

@@ -127,7 +127,7 @@
 
 <script setup lang="ts">
 import { ref, watch } from 'vue'
-import axios from 'axios'
+import api from '../utils/api'
 import { ElMessage } from 'element-plus'
 import { MagicStick, Loading, InfoFilled, List, Paperclip } from '@element-plus/icons-vue'
 import PinnedProject from './PinnedProject.vue'
@@ -175,11 +175,11 @@ watch(dateRange, (newDateRange) => {
 // 从数据库加载最新的 AI 推荐
 const loadLatestRecommendations = async () => {
   try {
-    const response = await axios.get('/api/ai/latest-recommendations')
+    const response = await api.get('/api/ai/latest-recommendations')
     const recommendations = response.data
     
     // 获取所有置顶的项目
-    const pinnedResponse = await axios.get('/api/bids/pinned')
+    const pinnedResponse = await api.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
@@ -240,7 +240,7 @@ const fetchAIRecommendations = async () => {
     }))
 
     // 调用后端 API
-    const response = await axios.post('/api/ai/recommendations', {
+    const response = await api.post('/api/ai/recommendations', {
       bids: bidsData
     })
 
@@ -267,7 +267,7 @@ const fetchAIRecommendations = async () => {
     aiRecommendations.value = recommendations
 
     // 保存推荐结果到数据库
-    await axios.post('/api/ai/save-recommendations', {
+    await api.post('/api/ai/save-recommendations', {
       recommendations
     })
 
@@ -301,7 +301,7 @@ const fetchBidsByDateRange = async () => {
       params.endDate = endDate
     }
 
-    const response = await axios.get('/api/bids/by-date-range', { params })
+    const response = await api.get('/api/bids/by-date-range', { params })
     bidsByDateRange.value = response.data
     ElMessage.success(`获取成功，共 ${response.data.length} 个工程`)
   } catch (error: any) {
@@ -344,7 +344,7 @@ const handlePinChanged = async (title: string) => {
 const togglePin = async (item: AIRecommendation) => {
   try {
     const newPinStatus = !item.pin
-    await axios.patch(`/api/bids/${encodeURIComponent(item.title)}/pin`, { pin: newPinStatus })
+    await api.patch(`/api/bids/${encodeURIComponent(item.title)}/pin`, { pin: newPinStatus })
     item.pin = newPinStatus
     ElMessage.success(newPinStatus ? '已置顶' : '已取消置顶')
     // 刷新 PinnedProject 组件的数据