feat: 实现前端卡密管理界面

- 卡密列表展示与分页功能

- 单个/批量创建卡密

- 卡密删除与批量删除

- 卡密导出功能 (file-saver)

- 启用/禁用状态切换

- 状态判断 (有效/已使用/已失效)

- Toast 通知系统 (vue-sonner)

- 登录页面错误提示优化

- 后端登录错误消息中文化

frontend/src/components/ui/checkbox/Checkbox.vue

@@ -0,0 +1,35 @@
+<script setup lang="ts">
+import type { CheckboxRootEmits, CheckboxRootProps } from "reka-ui"
+import type { HTMLAttributes } from "vue"
+import { reactiveOmit } from "@vueuse/core"
+import { Check } from "lucide-vue-next"
+import { CheckboxIndicator, CheckboxRoot, useForwardPropsEmits } from "reka-ui"
+import { cn } from "@/lib/utils"
+
+const props = defineProps<CheckboxRootProps & { class?: HTMLAttributes["class"] }>()
+const emits = defineEmits<CheckboxRootEmits>()
+
+const delegatedProps = reactiveOmit(props, "class")
+
+const forwarded = useForwardPropsEmits(delegatedProps, emits)
+</script>
+
+<template>
+  <CheckboxRoot
+    v-slot="slotProps"
+    data-slot="checkbox"
+    v-bind="forwarded"
+    :class="
+      cn('peer border-input data-[state=checked]:bg-primary data-[state=checked]:text-primary-foreground data-[state=checked]:border-primary focus-visible:border-ring focus-visible:ring-ring/50 aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive size-4 shrink-0 rounded-[4px] border shadow-xs transition-shadow outline-none focus-visible:ring-[3px] disabled:cursor-not-allowed disabled:opacity-50',
+         props.class)"
+  >
+    <CheckboxIndicator
+      data-slot="checkbox-indicator"
+      class="grid place-content-center text-current transition-none"
+    >
+      <slot v-bind="slotProps">
+        <Check class="size-3.5" />
+      </slot>
+    </CheckboxIndicator>
+  </CheckboxRoot>
+</template>