fix: 配置提交500 — 修正静态文件路径 + 启动时创建目录

- par.static.path 默认 ./static（不再重复 configs/）
- @PostConstruct 确保 static/configs 目录存在
- submitConfig 异常时详细日志

par-api/src/main/resources/application.yml

@@ -45,7 +45,7 @@ mybatis-plus:
 
 par:
   static:
-    path: ${PAR_STATIC_PATH:./static/configs/}
+    path: ${PAR_STATIC_PATH:./static}
   mediabot:
     psk: ${PAR_MEDIABOT_PSK:}
   admin: