feat(导航): 添加其他网站页面和URL卡片组件

添加新的"其他网站"导航页面，包含多个外部链接
实现URL卡片组件用于美观展示外部链接，支持自动获取元数据
调整导航栏配置和样式以适配新功能

astro.config.mjs

@@ -15,6 +15,7 @@ import remarkSectionize from "remark-sectionize";
 import { imageFallbackConfig, siteConfig } from "./src/config.ts";
 import { AdmonitionComponent } from "./src/plugins/rehype-component-admonition.mjs";
 import { GithubCardComponent } from "./src/plugins/rehype-component-github-card.mjs";
+import { UrlCardComponent } from "./src/plugins/rehype-component-url-card.mjs";
 import rehypeImageFallback from "./src/plugins/rehype-image-fallback.mjs";
 import { parseDirectiveNode } from "./src/plugins/remark-directive-rehype.js";
 import { remarkExcerpt } from "./src/plugins/remark-excerpt.js";
@@ -141,6 +142,7 @@ export default defineConfig({
                 {
                     components: {
                         github: GithubCardComponent,
+                        url: UrlCardComponent,
                         note: (x, y) => AdmonitionComponent(x, y, "note"),
                         tip: (x, y) => AdmonitionComponent(x, y, "tip"),
                         important: (x, y) => AdmonitionComponent(x, y, "important"),