refine: center toast notifications and silence plugin sync feedback

- Change toast position from top-right to top-center for better visibility
- Remove success notifications for plugin sync operations to reduce noise
- Keep error notifications to alert users of actual issues

src/components/ui/sonner.tsx

@@ -3,7 +3,7 @@ import { Toaster as SonnerToaster } from "sonner";
 export function Toaster() {
   return (
     <SonnerToaster
-      position="top-right"
+      position="top-center"
       richColors
       theme="system"
       toastOptions={{

src/hooks/useProviderActions.ts

@@ -39,16 +39,7 @@ export function useProviderActions(activeApp: AppType) {
         const isOfficial = provider.category === "official";
         await settingsApi.applyClaudePluginConfig({ official: isOfficial });
 
-        toast.success(
+        // 静默执行，不显示成功通知
-          isOfficial
-            ? t("notifications.appliedToClaudePlugin", {
-                defaultValue: "已同步为官方配置",
-              })
-            : t("notifications.removedFromClaudePlugin", {
-                defaultValue: "已移除 Claude 插件配置",
-              }),
-          { duration: 2200 },
-        );
       } catch (error) {
         const detail =
           extractErrorMessage(error) ||