fix: 修复添加记录后首页数据不刷新的问题

将缓存清除逻辑从 stats.js 路由移至 app.js 全局中间件，
确保 records.js 路由的写操作也能触发缓存清除。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/routes/stats.js

@@ -3,50 +3,11 @@ const db = require('../db');
 const config = require('../config');
 const logger = require('../utils/logger');
 const { getMonthRange, AppError, validateRequired, validateNumber, validateInList } = require('../utils/helpers');
+const { getCached } = require('../utils/cache');
 
 const router = express.Router();
 
-// 内存缓存（限制大小，基于LRU）
-const statsCache = new Map();
-const CACHE_TTL = config.cache.ttl;
-const MAX_CACHE_SIZE = config.cache.maxSize;
-
-function getCached(key, fetchFn) {
-  const cached = statsCache.get(key);
-  if (cached && Date.now() - cached.ts < CACHE_TTL) {
-    // LRU: move to end
-    statsCache.delete(key);
-    statsCache.set(key, cached);
-    return Promise.resolve(cached.data);
-  }
-  if (statsCache.size >= MAX_CACHE_SIZE) {
-    // Delete oldest entry
-    const firstKey = statsCache.keys().next().value;
-    statsCache.delete(firstKey);
-  }
-  return Promise.resolve(fetchFn()).then(data => {
-    statsCache.set(key, { data, ts: Date.now() });
-    logger.debug(`缓存更新: ${key}`);
-    return data;
-  }).catch(err => {
-    logger.error('缓存获取失败:', err.message);
-    throw err;
-  });
-}
-
-// POST/DELETE/PUT/PATCH 后清除当前用户的缓存
-router.use((req, res, next) => {
-  res.once('finish', () => {
-    if (['POST', 'DELETE', 'PUT', 'PATCH'].includes(req.method) && req.user?.id) {
-      for (const key of statsCache.keys()) {
-        if (key.includes(`:${req.user.id}:`)) {
-          statsCache.delete(key);
-        }
-      }
-    }
-  });
-  next();
-});
+// 缓存模块已移至 utils/cache.js
 
 // 格式化本地日期为 YYYY-MM-DD
 function formatLocalDate(date) {