feat: 趋势数据库从12条扩至30条，保留7天

client/src/pages/trend/trend.vue

@@ -87,7 +87,7 @@ const displayItems = computed(() => {
 async function fetchTrends() {
   loading.value = true
   try {
-    const data = await trendApi.list({ limit: 20 })
+    const data = await trendApi.list({ limit: 30 })
     items.value = data.list || data.items || []
   } catch (err) {
     console.error('获取趋势失败:', err)

server/src/scripts/update-trends.js

@@ -14,8 +14,8 @@ const mongoose = require('mongoose');
 const https = require('https');
 
 const DB_URI = process.env.MONGODB_URI || 'mongodb://127.0.0.1:27017/wdkj';
-const MAX_ITEMS = 12;
-const MAX_AGE_DAYS = 5;
+const MAX_ITEMS = 30;
+const MAX_AGE_DAYS = 7;
 
 // 精确 AI 关键词（只匹配这些才采信，避免噪音）
 const AI_KEYWORDS = [
@@ -167,7 +167,7 @@ async function main() {
 
   // 如果不够，补保底
   if (items.length < 6) {
-    const need = Math.min(FALLBACK.length, 12 - items.length);
+    const need = Math.min(FALLBACK.length, MAX_ITEMS - items.length);
     const fallback = FALLBACK.slice(0, need).map(f => ({ ...f, newsDate: f.newsDate() }));
     items.push(...fallback);
     console.log(`  ✓ 保底: ${need} 条`);