feat(admin): add initial admin dashboard structure

This commit introduces the foundational structure for the new admin dashboard.

- Utilizes @nuxt/ui to build the dashboard layout, including a collapsible sidebar and navigation.
- Adds initial pages for the dashboard, news, events, and hall of fame management.
- Implements a composable `useDashboardSidebarLinks` for managing sidebar navigation.
- Refactors the default layout by integrating the header and footer directly.
- Swaps the primary and secondary theme colors across the application.

app/components/admin/contents/news/AddModal.vue

@@ -0,0 +1,52 @@
+<template>
+  <UModal v-model:open="open" title="撰写新闻" description="在数据库中添加一篇新闻">
+    <UButton label="撰写新闻" icon="mdi:newspaper-plus" />
+
+    <template #body>
+      <UForm :schema="newsSchema" :state="newsState" @submit="onSubmit">
+        <UFormField label="新闻标题" name="title">
+          <UInput v-model="newsState.title" placeholder="请输入新闻标题" class="w-full" />
+        </UFormField>
+        <UFormField label="新闻内容" name="contents">
+          <UTextarea v-model="newsState.content" class="w-full" />
+        </UFormField>
+        这里应该是要有一个 Markdown 编辑界面
+        <div class="flex justify-end gap-2">
+          <UButton label="Cancel" color="neutral" variant="subtle" @click="open = false" />
+          <UButton label="Create" color="primary" variant="solid" type="submit" />
+        </div>
+      </UForm>
+    </template>
+  </UModal>
+</template>
+
+<script lang="ts" setup>
+import type { FormSubmitEvent } from '@nuxt/ui';
+import * as z from 'zod'
+
+const open = ref(false);
+
+const newsSchema = z.object({
+  title: z.string().min(2, '标题太短了容易产生歧义，请写长一些').max(15, '标题太长了影响阅读体验，请简短一些'),
+  content: z.string()
+})
+
+type NewsSchema = z.output<typeof newsSchema>
+
+const newsState = reactive<Partial<NewsSchema>>({
+  title: undefined,
+  content: undefined
+})
+
+const toast = useToast();
+const onSubmit = async (event: FormSubmitEvent<NewsSchema>) => {
+  toast.add({
+    title: "成功",
+    description: `${event.data.title} 新闻稿已经撰写完毕`,
+    color: 'success'
+  })
+  open.value = false
+}
+</script>
+
+<style></style>