chore(brand): surface ccswitch.io as the sole official website

Add an "Only Official Website" header to the three READMEs, an
About panel button, and a tray menu entry — all pointing to
ccswitch.io. Consolidates brand and SEO signals on the canonical
domain across docs, GUI, and system tray.

src/components/settings/AboutSection.tsx

@@ -3,6 +3,7 @@ import {
   Download,
   Copy,
   ExternalLink,
+  Globe,
   Info,
   Loader2,
   RefreshCw,
@@ -360,6 +361,16 @@ export function AboutSection({ isPortable }: AboutSectionProps) {
           </div>
 
           <div className="flex items-center gap-2">
+            <Button
+              type="button"
+              variant="outline"
+              size="sm"
+              onClick={() => settingsApi.openExternal("https://ccswitch.io")}
+              className="h-8 gap-1.5 text-xs"
+            >
+              <Globe className="h-3.5 w-3.5" />
+              {t("settings.officialWebsite")}
+            </Button>
             <Button
               type="button"
               variant="outline"

src/i18n/locales/en.json

@@ -643,6 +643,7 @@
     "releaseNotes": "Release Notes",
     "viewReleaseNotes": "View release notes for this version",
     "viewCurrentReleaseNotes": "View current version release notes",
+    "officialWebsite": "Official Website",
     "oneClickInstall": "One-click Install",
     "oneClickInstallHint": "Install Claude Code / Codex / Gemini CLI / OpenCode",
     "localEnvCheck": "Local environment check",

src/i18n/locales/ja.json

@@ -643,6 +643,7 @@
     "releaseNotes": "リリースノート",
     "viewReleaseNotes": "このバージョンのリリースノートを見る",
     "viewCurrentReleaseNotes": "現在のバージョンのリリースノートを見る",
+    "officialWebsite": "公式サイト",
     "oneClickInstall": "ワンクリックインストール",
     "oneClickInstallHint": "Claude Code / Codex / Gemini CLI / OpenCode をインストール",
     "localEnvCheck": "ローカル環境チェック",

src/i18n/locales/zh.json

@@ -643,6 +643,7 @@
     "releaseNotes": "更新日志",
     "viewReleaseNotes": "查看该版本更新日志",
     "viewCurrentReleaseNotes": "查看当前版本更新日志",
+    "officialWebsite": "官方网站",
     "oneClickInstall": "一键安装",
     "oneClickInstallHint": "安装 Claude Code / Codex / Gemini CLI / OpenCode",
     "localEnvCheck": "本地环境检查",