fix(i18n): localize Codex managed-account none option label

ProviderForm passed a hardcoded Chinese string as codexOauthNoneOptionLabel,
so en/ja/zh-TW users saw Chinese text in the Codex account selector's
"none" option. Add codexOauth.noneOptionLabel to all four locales and
resolve it via t().

src/components/providers/forms/ProviderForm.tsx

@@ -2100,7 +2100,7 @@ function ProviderFormFull({
               selectedCodexAccountId={selectedCodexAccountId}
               onCodexAccountSelect={setSelectedCodexAccountId}
               onManageAuthAccounts={onManageAuthAccounts}
-              codexOauthNoneOptionLabel="暂不绑定托管账号，使用浏览器登录"
+              codexOauthNoneOptionLabel={t("codexOauth.noneOptionLabel")}
               shouldShowSpeedTest={shouldShowSpeedTest}
               codexBaseUrl={codexBaseUrl}
               onBaseUrlChange={handleCodexBaseUrlChange}

src/i18n/locales/en.json

@@ -1170,6 +1170,7 @@
     "selectAccount": "Select account",
     "selectAccountPlaceholder": "Choose a ChatGPT account",
     "useDefaultAccount": "Use default account",
+    "noneOptionLabel": "Don't bind a managed account, use browser login",
     "loggedInAccounts": "Logged in accounts",
     "defaultAccount": "Default",
     "selected": "Selected",

src/i18n/locales/ja.json

@@ -1170,6 +1170,7 @@
     "selectAccount": "アカウントを選択",
     "selectAccountPlaceholder": "ChatGPT アカウントを選択",
     "useDefaultAccount": "デフォルトアカウントを使用",
+    "noneOptionLabel": "管理アカウントをバインドせず、ブラウザでログイン",
     "loggedInAccounts": "ログイン済みアカウント",
     "defaultAccount": "デフォルト",
     "selected": "選択中",

src/i18n/locales/zh-TW.json

@@ -1142,6 +1142,7 @@
     "selectAccount": "選擇帳號",
     "selectAccountPlaceholder": "選擇一個 ChatGPT 帳號",
     "useDefaultAccount": "使用預設帳號",
+    "noneOptionLabel": "暫不綁定託管帳號，使用瀏覽器登入",
     "loggedInAccounts": "已登入帳號",
     "defaultAccount": "預設",
     "selected": "已選取",

src/i18n/locales/zh.json

@@ -1170,6 +1170,7 @@
     "selectAccount": "选择账号",
     "selectAccountPlaceholder": "选择一个 ChatGPT 账号",
     "useDefaultAccount": "使用默认账号",
+    "noneOptionLabel": "暂不绑定托管账号，使用浏览器登录",
     "loggedInAccounts": "已登录账号",
     "defaultAccount": "默认",
     "selected": "已选中",