chore: rebrand product as 省心推 and lock UI to zh-CN

Update server titles, web/desktop window/tray/document titles, login
copy, and electron build metadata to use the Chinese product name 省心推.
Drop the runtime locale switcher and en-US import — the app now ships
zh-CN only.

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

apps/desktop-client/src/main/runtime-snapshot.ts

@@ -165,7 +165,7 @@ function createLiveRuntimeSnapshot(controller: RuntimeControllerSnapshot) {
   return {
     generatedAt: now,
     app: {
-      name: "GEO Rankly Desktop",
+      name: "省心推",
       version: app.getVersion(),
       channel: process.env.NODE_ENV === "development" ? "dev" : "release",
       platform: process.platform,