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/bootstrap.ts

@@ -340,7 +340,7 @@ async function createAppWindow(mode: WindowMode): Promise<ElectronBrowserWindow>
     minWidth: initial.minWidth,
     minHeight: initial.minHeight,
     show: false,
-    title: "GEO Rankly Desktop",
+    title: "省心推",
     icon: createDesktopHealthIcon("normal"),
     titleBarStyle: "hiddenInset",
     trafficLightPosition: { x: 12, y: 14 },
@@ -414,7 +414,7 @@ async function createSettingsWindow(): Promise<ElectronBrowserWindow> {
     minWidth: initial.minWidth,
     minHeight: initial.minHeight,
     show: false,
-    title: "GEO Rankly Desktop 设置",
+    title: "省心推设置",
     icon: createDesktopHealthIcon("normal"),
     titleBarStyle: "hiddenInset",
     trafficLightPosition: { x: 14, y: 15 },