feat: 添加关于对话框并优化主题切换按钮样式

- 新增 AboutModal 组件显示应用版本和相关信息
- 重构 ThemeToggle 组件为更简洁的图标按钮
- 在侧边栏添加关于按钮并实现打开对话框功能
- 通过预加载脚本获取 package.json 版本号
- 支持命令行参数 --version/-v 显示版本号

src/App.vue

@@ -23,6 +23,7 @@
         @toggle-theme="toggleTheme"
         @select-category="selectCategory"
         @close="isSidebarOpen = false"
+        @open-about="openAboutModal"
       />
     </aside>
 
@@ -132,6 +133,11 @@
       @close="closeUninstallModal"
       @success="onUninstallSuccess"
     />
+
+    <AboutModal
+      :show="showAboutModal"
+      @close="closeAboutModal"
+    />
   </div>
 </template>
 
@@ -150,6 +156,7 @@ import DownloadDetail from "./components/DownloadDetail.vue";
 import InstalledAppsModal from "./components/InstalledAppsModal.vue";
 import UpdateAppsModal from "./components/UpdateAppsModal.vue";
 import UninstallConfirmModal from "./components/UninstallConfirmModal.vue";
+import AboutModal from "./components/AboutModal.vue";
 import {
   APM_STORE_BASE_URL,
   currentApp,
@@ -240,6 +247,7 @@ const updateLoading = ref(false);
 const updateError = ref("");
 const showUninstallModal = ref(false);
 const uninstallTargetApp: Ref<App | null> = ref(null);
+const showAboutModal = ref(false);
 
 /** 启动参数 --no-apm => 仅 Spark；--no-spark => 仅 APM；由主进程 IPC 提供 */
 const storeFilter = ref<"spark" | "apm" | "both">("both");
@@ -834,6 +842,14 @@ const uninstallInstalledApp = (app: App) => {
   requestUninstall(app);
 };
 
+const openAboutModal = () => {
+  showAboutModal.value = true;
+};
+
+const closeAboutModal = () => {
+  showAboutModal.value = false;
+};
+
 // TODO: 目前 APM 商店不能暂停下载
 const pauseDownload = (id: DownloadItem) => {
   const download = downloads.value.find((d) => d.id === id.id);