refactor: 收敛单用户模型并优化可访问性与响应式体验

- 后端移除 is_admin 权限字段与相关逻辑，统一为单用户系统模型
- 修复会话过期清理的时间比较方式（改为 RFC3339 参数比较）
- /api/config 聚合配置增加敏感字段脱敏，避免暴露 TURN/RustDesk 密钥与密码
- 配置更新日志改为摘要，避免打印完整配置内容
- 前端修复可点击卡片语义与键盘可达，补齐图标按钮可访问名称
- 调整弹窗与抽屉的响应式尺寸，优化多端显示与交互

web/src/components/AppLayout.vue

@@ -52,7 +52,7 @@ async function handleLogout() {
 </script>
 
 <template>
-  <div class="h-screen flex flex-col bg-background overflow-hidden">
+  <div class="h-screen h-dvh flex flex-col bg-background overflow-hidden">
     <!-- Header -->
     <header class="shrink-0 z-50 w-full border-b bg-background/95 backdrop-blur supports-[backdrop-filter]:bg-background/60">
       <div class="flex h-14 items-center px-4 max-w-full">
@@ -86,14 +86,14 @@ async function handleLogout() {
           </span>
 
           <!-- Theme Toggle -->
-          <Button variant="ghost" size="icon" @click="toggleTheme">
+          <Button variant="ghost" size="icon" :aria-label="t('common.toggleTheme')" @click="toggleTheme">
             <Sun class="h-4 w-4 rotate-0 scale-100 transition-all dark:-rotate-90 dark:scale-0" />
             <Moon class="absolute h-4 w-4 rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100" />
             <span class="sr-only">{{ t('common.toggleTheme') }}</span>
           </Button>
 
           <!-- Language Toggle -->
-          <Button variant="ghost" size="icon" @click="toggleLanguage">
+          <Button variant="ghost" size="icon" :aria-label="t('common.toggleLanguage')" @click="toggleLanguage">
             <Languages class="h-4 w-4" />
             <span class="sr-only">{{ t('common.toggleLanguage') }}</span>
           </Button>
@@ -101,7 +101,7 @@ async function handleLogout() {
           <!-- Mobile Menu -->
           <DropdownMenu>
             <DropdownMenuTrigger as-child class="md:hidden">
-              <Button variant="ghost" size="icon">
+              <Button variant="ghost" size="icon" :aria-label="t('common.menu')">
                 <Menu class="h-4 w-4" />
               </Button>
             </DropdownMenuTrigger>
@@ -119,7 +119,7 @@ async function handleLogout() {
           </DropdownMenu>
 
           <!-- Logout Button (Desktop) -->
-          <Button variant="ghost" size="icon" class="hidden md:flex" @click="handleLogout">
+          <Button variant="ghost" size="icon" class="hidden md:flex" :aria-label="t('nav.logout')" @click="handleLogout">
             <LogOut class="h-4 w-4" />
             <span class="sr-only">{{ t('nav.logout') }}</span>
           </Button>

web/src/components/StatsSheet.vue

@@ -442,7 +442,7 @@ onUnmounted(() => {
   <Sheet :open="props.open" @update:open="emit('update:open', $event)">
     <SheetContent
       side="right"
-      class="w-[400px] sm:w-[440px] p-0 border-l border-slate-200 dark:border-slate-800 bg-white dark:bg-slate-950"
+      class="w-[90vw] max-w-[440px] p-0 border-l border-slate-200 dark:border-slate-800 bg-white dark:bg-slate-950"
     >
       <!-- Header -->
       <SheetHeader class="px-6 py-3 border-b border-slate-200 dark:border-slate-800">
@@ -454,7 +454,7 @@ onUnmounted(() => {
         </div>
       </SheetHeader>
 
-      <ScrollArea class="h-[calc(100vh-60px)]">
+      <ScrollArea class="h-[calc(100dvh-60px)]">
         <div class="px-6 py-4 space-y-6">
           <!-- Video Section Header -->
           <div>

web/src/components/StatusCard.vue

@@ -129,9 +129,11 @@ const statusBadgeText = computed(() => {
   <HoverCard v-if="!prefersPopover" :open-delay="200" :close-delay="100">
     <HoverCardTrigger as-child>
       <!-- New layout: vertical with title on top, status+quickInfo on bottom -->
-      <div
+      <button
+        type="button"
+        :aria-label="`${title}: ${quickInfo || subtitle || statusText}`"
         :class="cn(
-          'flex flex-col gap-0.5 rounded-md border cursor-pointer transition-colors',
+          'flex flex-col gap-0.5 rounded-md border cursor-pointer transition-colors text-left focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2',
           compact ? 'px-2 py-1 text-xs min-w-[80px]' : 'px-3 py-1.5 text-sm min-w-[100px]',
           'bg-white dark:bg-slate-800 hover:bg-slate-50 dark:hover:bg-slate-700',
           'border-slate-200 dark:border-slate-700',
@@ -147,7 +149,7 @@ const statusBadgeText = computed(() => {
             {{ quickInfo || subtitle || statusText }}
           </span>
         </div>
-      </div>
+      </button>
     </HoverCardTrigger>
 
     <HoverCardContent class="w-80" :align="hoverAlign">
@@ -228,9 +230,11 @@ const statusBadgeText = computed(() => {
   <Popover v-else>
     <PopoverTrigger as-child>
       <!-- New layout: vertical with title on top, status+quickInfo on bottom -->
-      <div
+      <button
+        type="button"
+        :aria-label="`${title}: ${quickInfo || subtitle || statusText}`"
         :class="cn(
-          'flex flex-col gap-0.5 rounded-md border cursor-pointer transition-colors',
+          'flex flex-col gap-0.5 rounded-md border cursor-pointer transition-colors text-left focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2',
           compact ? 'px-2 py-1 text-xs min-w-[80px]' : 'px-3 py-1.5 text-sm min-w-[100px]',
           'bg-white dark:bg-slate-800 hover:bg-slate-50 dark:hover:bg-slate-700',
           'border-slate-200 dark:border-slate-700',
@@ -246,7 +250,7 @@ const statusBadgeText = computed(() => {
             {{ quickInfo || subtitle || statusText }}
           </span>
         </div>
-      </div>
+      </button>
     </PopoverTrigger>
 
     <PopoverContent class="w-80" :align="hoverAlign">