fix(notifications): remove duplicate toast when switching to proxy providers

When switching to Copilot/ChatGPT/OpenAI-format providers with the proxy
not running, two toasts appeared: a "proxy required" warning followed by
a "switch success" toast. Unify the post-switch toast logic so that all
provider types show a single success toast, and skip it entirely when
a proxy-required warning was already shown.

src/hooks/useProviderActions.ts

@@ -200,27 +200,8 @@ export function useProviderActions(activeApp: AppId, isProxyRunning?: boolean) {
           );
         }
 
-        // 根据供应商类型显示不同的成功提示
-        if (
-          !proxyRequiredReason &&
-          activeApp === "claude" &&
-          provider.category !== "official" &&
-          (isCopilotProvider ||
-            provider.meta?.apiFormat === "openai_chat" ||
-            provider.meta?.apiFormat === "openai_responses")
-        ) {
-          // OpenAI format provider: show proxy hint (skip if warning already shown)
-          toast.info(
-            isCopilotProvider
-              ? t("notifications.copilotProxyHint")
-              : t("notifications.openAIFormatHint"),
-            {
-              duration: 5000,
-              closeButton: true,
-            },
-          );
-        } else {
-          // 普通供应商：显示切换成功
+        // 若已弹过 proxyRequired 警告则不再弹 success
+        if (!proxyRequiredReason) {
           // OpenCode/OpenClaw: show "added to config" message instead of "switched"
           const isMultiProviderApp =
             activeApp === "opencode" || activeApp === "openclaw";