refactor: improve date handling and timezone consistency

- Add timezone support to database module (+08:00)
- Extract date formatting utilities to shared modules
- Standardize timezone handling across frontend and backend
- Improve date formatting consistency in UI components
- Refactor crawler page.goto options for better readability

frontend/src/components/Bids.vue

@@ -54,6 +54,7 @@ import { ref } from 'vue'
 import api from '../utils/api'
 import { ElMessage } from 'element-plus'
 import { Paperclip } from '@element-plus/icons-vue'
+import { formatDate } from '../utils/date.util'
 
 interface Props {
   bids: any[]
@@ -72,11 +73,6 @@ const selectedSource = ref('')
 const currentPage = ref(1)
 const pageSize = ref(10)
 
-const formatDate = (dateString: string) => {
-  if (!dateString) return '-'
-  return new Date(dateString).toLocaleDateString()
-}
-
 const handleSourceChange = () => {
   currentPage.value = 1
   emit('fetch', currentPage.value, pageSize.value, selectedSource.value || undefined)

frontend/src/components/CrawlInfo.vue

@@ -16,12 +16,12 @@
         <el-table-column prop="count" label="本次获取数量" width="120" sortable />
         <el-table-column label="最近更新时间" width="180">
           <template #default="{ row }">
-            {{ formatDate(row.latestUpdate) }}
+            {{ formatDateTime(row.latestUpdate) }}
           </template>
         </el-table-column>
         <el-table-column label="最新工程时间" width="180">
           <template #default="{ row }">
-            {{ formatDate(row.latestPublishDate) }}
+            {{ formatDateTime(row.latestPublishDate) }}
           </template>
         </el-table-column>
         <el-table-column label="状态" width="100">
@@ -78,6 +78,7 @@ import { ref, computed, onMounted, onBeforeUnmount } from 'vue'
 import api from '../utils/api'
 import { ElMessage } from 'element-plus'
 import { Refresh } from '@element-plus/icons-vue'
+import { formatDateTime } from '../utils/date.util'
 
 interface CrawlStat {
   source: string
@@ -90,7 +91,6 @@ interface CrawlStat {
 const crawlStats = ref<CrawlStat[]>([])
 const loading = ref(false)
 const crawlingSources = ref<Set<string>>(new Set())
-const REFRESH_INTERVAL = 10000
 let refreshTimer: number | null = null
 
 const totalCount = computed(() => {
@@ -105,18 +105,6 @@ const errorSources = computed(() => {
   return crawlStats.value.filter(item => item.error && item.error.trim()).length
 })
 
-const formatDate = (dateStr: string | null) => {
-  if (!dateStr) return '-'
-  const date = new Date(dateStr)
-  return date.toLocaleString('zh-CN', {
-    year: 'numeric',
-    month: '2-digit',
-    day: '2-digit',
-    hour: '2-digit',
-    minute: '2-digit'
-  })
-}
-
 const fetchCrawlStats = async () => {
   loading.value = true
   try {

frontend/src/components/Dashboard.vue

@@ -81,6 +81,7 @@ import api from '../utils/api'
 import { ElMessage } from 'element-plus'
 import { Refresh, Paperclip } from '@element-plus/icons-vue'
 import PinnedProject from './PinnedProject.vue'
+import { formatDate } from '../utils/date.util'
 
 interface Props {
   todayBids: any[]
@@ -160,11 +161,6 @@ watch(dateRange, () => {
   }
 })
 
-const formatDate = (dateString: string) => {
-  if (!dateString) return '-'
-  return new Date(dateString).toLocaleDateString()
-}
-
 // 过滤 Today's Bids，只显示包含所选关键字的项目，并且在日期范围内
 const filteredTodayBids = computed(() => {
   let result = props.todayBids

frontend/src/components/PinnedProject.vue

@@ -38,7 +38,7 @@
         <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) }}
+            {{ formatSimpleDate(scope.row.publishDate) }}
           </template>
         </el-table-column>
       </el-table>
@@ -51,6 +51,7 @@ import { ref, onMounted } from 'vue'
 import api from '../utils/api'
 import { ElMessage } from 'element-plus'
 import { Loading, InfoFilled, Paperclip } from '@element-plus/icons-vue'
+import { formatSimpleDate } from '../utils/date.util'
 
 const emit = defineEmits<{
   pinChanged: [title: string]
@@ -88,16 +89,6 @@ const togglePin = async (item: any) => {
   }
 }
 
-// 格式化日期，只显示年月日
-const formatDate = (dateStr: string) => {
-  if (!dateStr) return ''
-  const date = new Date(dateStr)
-  const year = date.getFullYear()
-  const month = String(date.getMonth() + 1).padStart(2, '0')
-  const day = String(date.getDate()).padStart(2, '0')
-  return `${year}-${month}-${day}`
-}
-
 // 初始化时加载置顶项目
 onMounted(() => {
   loadPinnedBids()

frontend/src/utils/date.util.ts

@@ -0,0 +1,58 @@
+/**
+ * 日期格式化工具函数
+ * 统一处理东八区(Asia/Shanghai)时间显示
+ */
+
+/**
+ * 格式化日期为 YYYY-MM-DD 格式
+ * @param dateStr 日期字符串或Date对象
+ * @returns 格式化后的日期字符串
+ */
+export function formatDate(dateStr: string | null | undefined): string {
+  if (!dateStr) return '-'
+  const date = new Date(dateStr)
+  if (isNaN(date.getTime())) return '-'
+  
+  return date.toLocaleDateString('zh-CN', {
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+    timeZone: 'Asia/Shanghai'
+  }).replace(/\//g, '-')
+}
+
+/**
+ * 格式化日期时间为 YYYY-MM-DD HH:mm 格式
+ * @param dateStr 日期字符串或Date对象
+ * @returns 格式化后的日期时间字符串
+ */
+export function formatDateTime(dateStr: string | null | undefined): string {
+  if (!dateStr) return '-'
+  const date = new Date(dateStr)
+  if (isNaN(date.getTime())) return '-'
+  
+  return date.toLocaleString('zh-CN', {
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+    hour: '2-digit',
+    minute: '2-digit',
+    timeZone: 'Asia/Shanghai'
+  }).replace(/\//g, '-')
+}
+
+/**
+ * 格式化日期为简洁的 YYYY-MM-DD 格式（用于置顶项目等）
+ * @param dateStr 日期字符串或Date对象
+ * @returns 格式化后的日期字符串
+ */
+export function formatSimpleDate(dateStr: string | null | undefined): string {
+  if (!dateStr) return ''
+  const date = new Date(dateStr)
+  if (isNaN(date.getTime())) return ''
+  
+  const year = date.getFullYear()
+  const month = String(date.getMonth() + 1).padStart(2, '0')
+  const day = String(date.getDate()).padStart(2, '0')
+  return `${year}-${month}-${day}`
+}