feat: PM2 + Docker deployment config (MySQL container, PM2 for backend+frontend proxy)

.env.example

@@ -0,0 +1,15 @@
+# 恭学教育 — 生产环境配置
+# 复制为 .env 并修改密码
+
+# MySQL 数据库
+MYSQL_ROOT_PASSWORD=change-me-to-a-strong-password
+
+# 后端
+DB_HOST=127.0.0.1
+DB_PORT=3306
+DB_USERNAME=root
+DB_DATABASE=gongxue
+DB_SYNCHRONIZE=false
+JWT_SECRET=change-me-to-a-random-string-at-least-32-chars
+JWT_EXPIRES_IN=24h
+PORT=3000