refactor: 备案号改为环境变量配置

ICP 和公安备案号通过 NUXT_PUBLIC_ICP / NUXT_PUBLIC_PS_BEIAN 环境变量读取，
空值时底部不显示。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/layout/Footer.vue

@@ -1,19 +1,25 @@
 <script setup lang="ts">
 import { siteConfig } from '~/config/site'
+
+const config = useRuntimeConfig()
+const icp = config.public.icp
+const psBeian = config.public.psBeian
 </script>
 
 <template>
   <footer class="py-6 text-center text-sm border-t" style="color: var(--color-text-secondary); border-color: var(--color-border);">
     <p>
       &copy; {{ new Date().getFullYear() }} {{ siteConfig.siteName }}
-      <template v-if="siteConfig.icp">
+      <template v-if="icp">
         &nbsp;·&nbsp;
-        <a href="https://beian.miit.gov.cn/" target="_blank" rel="noopener noreferrer" class="hover:opacity-70" style="border-bottom: 1px solid var(--color-text-secondary); padding-bottom: 1px;">{{ siteConfig.icp }}</a>
+        <a href="https://beian.miit.gov.cn/" target="_blank" rel="noopener noreferrer" class="hover:opacity-70" style="border-bottom: 1px solid var(--color-text-secondary); padding-bottom: 1px;">{{ icp }}</a>
+      </template>
+      <template v-if="psBeian">
+        &nbsp;·&nbsp;
+        <a :href="`https://beian.mps.gov.cn/#/query/webSearch?code=${psBeian}`" rel="noreferrer" target="_blank" class="hover:opacity-70" style="border-bottom: 1px solid var(--color-text-secondary); padding-bottom: 1px;">
+          <img src="@/assets/备案图标.png" alt="" class="w-3 h-3 inline" />川公网安备{{ psBeian }}号
+        </a>
       </template>
-      &nbsp;·&nbsp;
-      <a href="https://beian.mps.gov.cn/#/query/webSearch?code=51015602001952" rel="noreferrer" target="_blank" class="hover:opacity-70" style="border-bottom: 1px solid var(--color-text-secondary); padding-bottom: 1px;">
-        <img src="@/assets/备案图标.png" alt="" class="w-3 h-3 inline" />川公网安备51015602001952号
-      </a>
     </p>
   </footer>
 </template>