Add unplugin-icons & use Mingcute icons

Register unplugin-icons (Icons Vite plugin) in astro.config and add unplugin-icons + @iconify-json/mingcute to devDependencies. Replace inline SVGs in ThemeSwitcher.vue with MingcuteSunLine / MingcuteMoonLine icon components imported from ~icons, and add unplugin-icons types to tsconfig. Also simplify VSCode formatter setting and update package.json accordingly.

astro.config.mjs

@@ -2,6 +2,7 @@
 import { defineConfig } from "astro/config";
 
 import vue from "@astrojs/vue";
+import Icons from "unplugin-icons/vite";
 
 export default defineConfig({
   base: "/themes/astro-starter",
@@ -11,4 +12,11 @@ export default defineConfig({
   },
   outDir: "./templates",
   integrations: [vue()],
+  vite: {
+    plugins: [
+      Icons({
+        compiler: "vue3",
+      }),
+    ],
+  },
 });