chore: 将全屏按钮置于顶部，使其显眼且易于操作 (#969)

* chore: 将全屏按钮置于顶部，使其显眼且易于操作

src/layout/components/sidebar/fullScreen.vue

@@ -0,0 +1,30 @@
+<script setup lang="ts">
+import { ref, watch } from "vue";
+import { useNav } from "@/layout/hooks/useNav";
+
+const screenIcon = ref();
+const { toggle, isFullscreen, Fullscreen, ExitFullscreen } = useNav();
+
+isFullscreen.value = !!(
+  document.fullscreenElement ||
+  document.webkitFullscreenElement ||
+  document.mozFullScreenElement ||
+  document.msFullscreenElement
+);
+
+watch(
+  isFullscreen,
+  full => {
+    screenIcon.value = full ? ExitFullscreen : Fullscreen;
+  },
+  {
+    immediate: true
+  }
+);
+</script>
+
+<template>
+  <span class="fullscreen-icon navbar-bg-hover" @click="toggle">
+    <IconifyIconOffline :icon="screenIcon" />
+  </span>
+</template>