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/pagination/PaginationPrevious.vue

@@ -0,0 +1,33 @@
+<script setup lang="ts">
+import type { PaginationPrevProps } from "reka-ui"
+import type { HTMLAttributes } from "vue"
+import type { ButtonVariants } from '@/components/ui/button'
+import { reactiveOmit } from "@vueuse/core"
+import { ChevronLeftIcon } from "lucide-vue-next"
+import { PaginationPrev, useForwardProps } from "reka-ui"
+import { cn } from "@/lib/utils"
+import { buttonVariants } from '@/components/ui/button'
+
+const props = withDefaults(defineProps<PaginationPrevProps & {
+  size?: ButtonVariants["size"]
+  class?: HTMLAttributes["class"]
+}>(), {
+  size: "default",
+})
+
+const delegatedProps = reactiveOmit(props, "class", "size")
+const forwarded = useForwardProps(delegatedProps)
+</script>
+
+<template>
+  <PaginationPrev
+    data-slot="pagination-previous"
+    :class="cn(buttonVariants({ variant: 'ghost', size }), 'gap-1 px-2.5 sm:pr-2.5', props.class)"
+    v-bind="forwarded"
+  >
+    <slot>
+      <ChevronLeftIcon />
+      <span class="hidden sm:block">Previous</span>
+    </slot>
+  </PaginationPrev>
+</template>