fix: remove unused imports and leftover jsx in settings

vite-frontend/src/pages/settings.tsx

@@ -1,4 +1,4 @@
-import { useState, useEffect, useRef, ChangeEvent } from "react";
+import { useState, useEffect } from "react";
 import { useNavigate } from "react-router-dom";
 import toast from "react-hot-toast";
 
@@ -23,7 +23,6 @@ import {
   deletePanelAddress,
   validatePanelAddress,
 } from "@/utils/panel";
-import { siteConfig, updateSiteConfig } from "@/config/site";
 
 interface PanelAddress {
   name: string;
@@ -184,83 +183,6 @@ export const SettingsPage = () => {
       {/* 内容区域 */}
       <div className="max-w-4xl mx-auto px-4 py-6">
         <div className="space-y-6">
-          <Card>
-            <CardBody className="p-6">
-              <h2 className="text-lg font-medium text-gray-900 dark:text-white mb-4">
-                外观设置
-              </h2>
-              <div className="space-y-4">
-                <div className="flex flex-col gap-2">
-                  <div>
-                    <label className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-1">
-                      自定义背景图片
-                    </label>
-                    <p className="text-xs text-gray-500 dark:text-gray-400 mb-3">
-                      留空则使用系统默认的网格渐变背景。推荐上传 1920x1080 尺寸的图片。
-                    </p>
-                    <div className="flex items-center gap-4">
-                      {bgImage ? (
-                        <div className="relative w-40 h-24 rounded-md overflow-hidden border border-gray-200 dark:border-gray-700 group">
-                          <img src={bgImage} alt="Background Preview" className="w-full h-full object-cover" />
-                        </div>
-                      ) : (
-                        <div className="flex items-center justify-center w-40 h-24 rounded-md border border-dashed border-gray-300 dark:border-gray-600 bg-gray-50 dark:bg-gray-800 text-gray-400 text-xs">
-                          无自定义背景
-                        </div>
-                      )}
-                      <div>
-                        <input
-                          type="file"
-                          accept="image/*"
-                          className="hidden"
-                          ref={fileInputRef}
-                          onChange={handleBgImageUpload}
-                        />
-                        <Button
-                          color="primary"
-                          variant="flat"
-                          size="sm"
-                          isDisabled={!admin || bgImageSaving}
-                          onPress={() => fileInputRef.current?.click()}
-                        >
-                          选择图片...
-                        </Button>
-                      </div>
-                    </div>
-                  </div>
-                  <div className="flex justify-end gap-2 mt-2">
-                    {bgImage && (
-                      <Button
-                        color="danger"
-                        variant="flat"
-                        isDisabled={!admin || bgImageSaving}
-                        onPress={() => {
-                          setBgImage("");
-                          void handleBgImageSave("");
-                        }}
-                      >
-                        恢复默认
-                      </Button>
-                    )}
-                    <Button 
-                      color="primary" 
-                      isDisabled={!admin}
-                      isLoading={bgImageSaving}
-                      onPress={() => handleBgImageSave()}
-                    >
-                      保存背景
-                    </Button>
-                  </div>
-                  {!admin && (
-                    <p className="mt-2 text-xs text-amber-600 dark:text-amber-400">
-                      仅管理员可修改该全局配置。
-                    </p>
-                  )}
-                </div>
-              </div>
-            </CardBody>
-          </Card>
-
           <Card>
             <CardBody className="p-6">
               <h2 className="text-lg font-medium text-gray-900 dark:text-white mb-4">