fix: mongo 连接重试（容器编排 DNS 竞态导致启动循环重启）

server/src/config/database.js

@@ -4,15 +4,25 @@ const mongoose = require('mongoose')
  * 数据库连接配置
  */
 const connectDB = async () => {
+  // 容器编排下 mongo 可能晚于应用就绪（DNS EAI_AGAIN），带重试启动
+  const mongoURI = process.env.MONGODB_URI ||
+    `mongodb://${process.env.MONGODB_USER}:${process.env.MONGODB_PASSWORD}@${process.env.MONGODB_HOST}:${process.env.MONGODB_PORT}/${process.env.MONGODB_DB}?authSource=${process.env.MONGODB_DB}`
+  const MAX_RETRIES = 10
+  let conn = null
+  for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
+    try {
+      conn = await mongoose.connect(mongoURI, {})
+      break
+    } catch (err) {
+      console.warn(`MongoDB 连接失败(${attempt}/${MAX_RETRIES}):`, err.message)
+      if (attempt === MAX_RETRIES) {
+        console.error('MongoDB 连接重试耗尽，进程退出')
+        process.exit(1)
+      }
+      await new Promise(r => setTimeout(r, 3000))
+    }
+  }
   try {
-    const mongoURI = process.env.MONGODB_URI || 
-      `mongodb://${process.env.MONGODB_USER}:${process.env.MONGODB_PASSWORD}@${process.env.MONGODB_HOST}:${process.env.MONGODB_PORT}/${process.env.MONGODB_DB}?authSource=${process.env.MONGODB_DB}`
-    
-    const conn = await mongoose.connect(mongoURI, {
-      // Mongoose 6+ 不再需要这些选项，但保留以兼容旧版本
-      // useNewUrlParser: true,
-      // useUnifiedTopology: true,
-    })
     
     console.log(`✅ MongoDB 连接成功: ${conn.connection.host}:${conn.connection.port}/${conn.connection.name}`)