feat(desktop-client): expand publisher error normalization

新增登录态失效与微信公众号外链缺失两类发布错误归一化，
将原本散落在适配器里的中文提示集中到 shared/publisher-errors，
让渲染层与 main 进程共用同一份用户可读文案。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/desktop-client/src/main/adapters/weixin-gzh.ts

@@ -8,6 +8,10 @@ import {
   sessionFetchText,
   uploadHtmlImages,
 } from "./common";
+import {
+  WEIXIN_GZH_PUBLIC_URL_MISSING_MESSAGE,
+  normalizeWeixinGzhPublishErrorMessage,
+} from "../../shared/publisher-errors";
 import {
   fetchImageAssetBlob,
   getCenteredCropRect,
@@ -1932,10 +1936,10 @@ function failureResult(error: unknown): ReturnType<PublishAdapter["publish"]> ex
   if (message.startsWith("weixin_gzh_public_url_missing")) {
     return {
       status: "failed",
-      summary: "微信公众号已提交发布，但未能获取外部文章链接，请在公众号后台发表记录确认。",
+      summary: WEIXIN_GZH_PUBLIC_URL_MISSING_MESSAGE,
       error: {
         code: "weixin_gzh_public_url_missing",
-        message,
+        message: normalizeWeixinGzhPublishErrorMessage(message) ?? WEIXIN_GZH_PUBLIC_URL_MISSING_MESSAGE,
       },
     };
   }