Fix Codex OAuth auth being cleared during preserve-mode takeover

When "preserve official auth on switch" is enabled, proxy takeover routes
the PROXY_MANAGED placeholder into config.toml's experimental_bearer_token
and leaves auth.json (the ChatGPT OAuth login) untouched. Takeover detection
only inspected auth.json's OPENAI_API_KEY, so it never recognized this state
and returned a false negative, which led downstream paths to clobber the
preserved OAuth login.

- Detection: is_codex_live_taken_over now also matches a config.toml
  experimental_bearer_token equal to the placeholder, fixing detect/cleanup/
  restore/startup-recovery in one place.
- Cleanup: remove the config.toml bearer token only when it equals the
  placeholder (new remove_codex_experimental_bearer_token_if predicate), so a
  real third-party key is never stripped.
- Write: under preservation, the None-provider takeover path writes only
  config.toml and keeps auth.json intact, matching the provider path.
- Settings: rename the section to "Codex App Enhancements" and reword the
  description across all four locales.
- Add tests covering OAuth preservation on takeover and placeholder-only
  cleanup.

src/components/settings/SettingsPage.tsx

@@ -242,11 +242,11 @@ export function SettingsPage({
                         handleAutoSave({ skillSyncMethod: method })
                       }
                     />
-                    <WindowSettings
+                    <CodexAuthSettings
                       settings={settings}
                       onChange={handleAutoSave}
                     />
-                    <CodexAuthSettings
+                    <WindowSettings
                       settings={settings}
                       onChange={handleAutoSave}
                     />

src/i18n/locales/en.json

@@ -562,9 +562,9 @@
     "enableClaudePluginIntegrationDescription": "When enabled, the VS Code Claude Code extension provider will switch with this app",
     "skipClaudeOnboarding": "Skip Claude Code first-run confirmation",
     "skipClaudeOnboardingDescription": "When enabled, Claude Code will skip the first-run confirmation",
-    "codexAuth": "Codex Authentication",
+    "codexAuth": "Codex App Enhancements",
     "preserveCodexOfficialAuthOnSwitch": "Keep official login when switching third-party providers",
-    "preserveCodexOfficialAuthOnSwitchDescription": "When enabled, third-party Codex switches update only config.toml and keep the ChatGPT login in auth.json. When disabled, auth.json is overwritten with the active provider auth.",
+    "preserveCodexOfficialAuthOnSwitchDescription": "When enabled, you can use the Codex app's official plugins, mobile remote control, and other features while using third-party APIs.",
     "appVisibility": {
       "title": "Homepage Display",
       "description": "Choose which apps to show on the homepage",

src/i18n/locales/ja.json

@@ -562,9 +562,9 @@
     "enableClaudePluginIntegrationDescription": "オンにすると VS Code の Claude Code 拡張のプロバイダーも同期します",
     "skipClaudeOnboarding": "Claude Code の初回確認をスキップ",
     "skipClaudeOnboardingDescription": "オンにすると Claude Code の初回インストール確認をスキップします",
-    "codexAuth": "Codex 認証",
+    "codexAuth": "Codex アプリ拡張",
     "preserveCodexOfficialAuthOnSwitch": "サードパーティ切替時に公式ログインを保持",
-    "preserveCodexOfficialAuthOnSwitchDescription": "オンにするとサードパーティ Codex への切替では config.toml のみ更新し、auth.json の ChatGPT ログインを保持します。オフにすると auth.json を現在のプロバイダー認証で上書きします。",
+    "preserveCodexOfficialAuthOnSwitchDescription": "オンにすると、サードパーティ API を使用する際に Codex アプリの公式プラグインやスマホからのリモート操作などの機能を利用できます。",
     "appVisibility": {
       "title": "ホームページ表示",
       "description": "ホームページに表示するアプリを選択",

src/i18n/locales/zh-TW.json

@@ -562,9 +562,9 @@
     "enableClaudePluginIntegrationDescription": "開啟後 Vscode Claude Code 外掛程式的供應商將隨本軟體切換",
     "skipClaudeOnboarding": "跳過 Claude Code 初次安裝確認",
     "skipClaudeOnboardingDescription": "開啟後跳過 Claude Code 初次安裝確認",
-    "codexAuth": "Codex 認證",
+    "codexAuth": "Codex 應用增強",
     "preserveCodexOfficialAuthOnSwitch": "切換第三方時保留官方登入",
-    "preserveCodexOfficialAuthOnSwitchDescription": "開啟後切換第三方 Codex 供應商只更新 config.toml，並保留 auth.json 中的 ChatGPT 登入狀態；關閉後會用目前供應商 auth 覆寫 auth.json。",
+    "preserveCodexOfficialAuthOnSwitchDescription": "開啟後可以在使用第三方 API 的時候使用 Codex 應用的官方外掛、手機遠端操作等功能",
     "appVisibility": {
       "title": "主頁面顯示",
       "description": "選擇在主頁面顯示的應用程式",

src/i18n/locales/zh.json

@@ -562,9 +562,9 @@
     "enableClaudePluginIntegrationDescription": "开启后 Vscode Claude Code 插件的供应商将随本软件切换",
     "skipClaudeOnboarding": "跳过 Claude Code 初次安装确认",
     "skipClaudeOnboardingDescription": "开启后跳过 Claude Code 初次安装确认",
-    "codexAuth": "Codex 认证",
+    "codexAuth": "Codex 应用增强",
     "preserveCodexOfficialAuthOnSwitch": "切换第三方时保留官方登录",
-    "preserveCodexOfficialAuthOnSwitchDescription": "开启后切换第三方 Codex 供应商只更新 config.toml，并保留 auth.json 中的 ChatGPT 登录态；关闭后会用当前供应商 auth 覆盖 auth.json。",
+    "preserveCodexOfficialAuthOnSwitchDescription": "开启后可以在使用第三方 API 的时候使用 Codex 应用的官方插件、手机远程操作等功能",
     "appVisibility": {
       "title": "主页面显示",
       "description": "选择在主页面显示的应用",