feat(layout): 重构页面布局与音乐播放组件

将 PlayMusic 组件迁移至 layout/RightButton 并重构成通用右下角按钮组件，
提取音乐播放逻辑到独立 hook `usePlayMusic`，优化模态框提示逻辑并统一滚动行为。

src/layout/index.vue

@@ -1,32 +1,36 @@
 <script setup lang="ts">
 import { useScroll } from '@vueuse/core'
-// import Header from './Header/index.vue';
-// import Footer from './Footer/index.vue';
 import { ref } from 'vue'
+import { useI18n } from 'vue-i18n'
+import CustomModal from '@/components/Dialog/index.vue'
 import { Loading } from '@/components/Loading'
 import ToTop from '@/components/ToTop/index.vue'
+import RightButton from './RightButton/index.vue'
+import { useMounted } from './useMounted'
 
+const tipDialog = ref()
+const { tipDesc } = useMounted(tipDialog)
+const { t } = useI18n()
 const mainContainer = ref<HTMLElement | null>(null)
 const { y } = useScroll(mainContainer)
 
 function scrollToTop() {
-  y.value = 0
+  mainContainer.value?.scrollTo({
+    top: 0,
+    behavior: 'smooth',
+  })
 }
 </script>
 
 <template>
   <div class="w-screen">
-    <!-- <header class="shadow-2xl head-container h-14">
-      <Header></Header>
-    </header> -->
     <Loading />
     <ToTop v-if="y > 400" @click="scrollToTop" />
     <main ref="mainContainer" class="box-content w-screen h-screen overflow-x-hidden overflow-y-auto main-container">
       <router-view class="h-full main-container-content" />
     </main>
-    <!-- <footer class="w-screen footer-container">
-      <Footer></Footer>
-    </footer> -->
+    <RightButton class="absolute right-0 bottom-1/2" />
+    <CustomModal ref="tipDialog" :title="t('dialog.titleTip')" :desc="tipDesc" />
   </div>
 </template>