重构后端API和配置，新增仪表板数据接口并优化本地开发环境配置

backend/config/env.js

@@ -5,7 +5,7 @@ require('dotenv').config({ path: path.join(__dirname, '../../.env') })
 const config = {
   // 开发环境
   development: {
-    port: process.env.PORT || 3110,
+    port: process.env.PORT || 3200,
     mysql: {
       host: process.env.DB_HOST || 'nj-cdb-3pwh2kz1.sql.tencentcdb.com',
       port: process.env.DB_PORT || 20784,
@@ -27,7 +27,7 @@ const config = {
       allowedTypes: ['image/jpeg', 'image/png', 'image/gif']
     },
     cors: {
-      origin: process.env.CORS_ORIGIN || 'https://www.jiebanke.com',
+      origin: process.env.CORS_ORIGIN || 'http://localhost:3150',
       credentials: true
     }
   },