feat(site): 对齐参考站点UI与交互调整

- 页脚：响应耗时文字统一为「响应耗时 XXXms」，版本链接改为 GitHub 官方仓库，默认 ICP 备案号设置为粤ICP备2025450093号
- 顶部栏：恢复主题切换按钮与语言按钮（语言暂为占位提示），放置于用户区左侧
- 主题：修复首屏内联脚本默认主题白名单校验，避免 localStorage 中残留的 light/dark/System 等非法值生效，首屏默认改为 ClassicLight（仅允许 ClassicLight/ModernLight）
- 登录页：在密码输入框下方恢复「忘记密码？」入口，新增配套的找回密码引导页 /forgot-password
- 默认配置：system-settings 兜底记录与 SYSTEM_SETTINGS_DEFAULTS 新增 icpNumber 默认值

app/pages/index.vue

@@ -33,6 +33,30 @@
         <!-- 用户信息区域 -->
         <div class="user-section">
           <ClientOnly>
+            <!-- 主题切换按钮 -->
+            <button
+              class="utility-btn theme-toggle-btn"
+              type="button"
+              aria-label="主题"
+              title="切换主题"
+              @click="handleToggleTheme"
+            >
+              <Icon :name="isDark ? 'sun' : 'moon'" :size="18" />
+              <span class="utility-btn-label">主题</span>
+            </button>
+
+            <!-- 语言切换按钮（占位按钮，当前单语种） -->
+            <button
+              class="utility-btn lang-toggle-btn"
+              type="button"
+              aria-label="语言"
+              title="语言"
+              @click="handleLanguageClick"
+            >
+              <Icon name="globe" :size="18" />
+              <span class="utility-btn-label">语言</span>
+            </button>
+
             <div v-if="isClientAuthenticated" class="user-info">
               <div class="user-details-desktop">
                 <span class="user-name">{{ user?.name || '用户' }}</span>
@@ -674,12 +698,24 @@ import ConfirmDialog from '~/components/UI/ConfirmDialog.vue'
 
 import { useNotifications } from '~/composables/useNotifications'
 import { useSiteConfig } from '~/composables/useSiteConfig'
+import { useTheme } from '~/composables/useTheme'
 import CustomSelect from '~/components/UI/Common/CustomSelect.vue'
 
 // 获取运行时配置
 const config = useRuntimeConfig()
 const router = useRouter()
 
+// 主题
+const { isDark, toggleTheme } = useTheme()
+const handleToggleTheme = () => {
+  toggleTheme()
+}
+const handleLanguageClick = () => {
+  if (typeof window !== 'undefined' && window.$showNotification) {
+    window.$showNotification('当前版本暂不支持多语言切换', 'info')
+  }
+}
+
 // 站点配置
 const {
   siteTitle,
@@ -1709,6 +1745,55 @@ if (
 .user-section {
   position: relative;
   z-index: 100;
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+/* 通用工具按钮（主题/语言） */
+.utility-btn {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  padding: 7px 12px;
+  background: var(--utility-btn-bg, rgba(255, 255, 255, 0.06));
+  color: var(--utility-btn-color, rgba(255, 255, 255, 0.78));
+  border: 1px solid var(--utility-btn-border, rgba(255, 255, 255, 0.12));
+  border-radius: 10px;
+  font-size: 13px;
+  font-weight: 500;
+  line-height: 1;
+  cursor: pointer;
+  transition:
+    background 0.2s ease,
+    color 0.2s ease,
+    border-color 0.2s ease,
+    transform 0.15s ease;
+  backdrop-filter: blur(6px);
+}
+
+.utility-btn:hover {
+  background: var(--utility-btn-hover-bg, rgba(255, 255, 255, 0.12));
+  color: var(--utility-btn-hover-color, #ffffff);
+  border-color: var(--utility-btn-hover-border, rgba(255, 255, 255, 0.22));
+}
+
+.utility-btn:active {
+  transform: scale(0.97);
+}
+
+.utility-btn-label {
+  white-space: nowrap;
+}
+
+@media (max-width: 768px) {
+  .utility-btn-label {
+    display: none;
+  }
+  .utility-btn {
+    padding: 7px 8px;
+    border-radius: 9px;
+  }
 }
 
 .user-info {