fix(i18n): add provider import menu keys

Supply missing codexMenu/claudeCodeMenu/customMenu labels, descs, and alreadyImported for both en and zh-CN so the '+ Add provider' dropdown renders localized text instead of raw keys.

Author: hqhq1025

packages/i18n/src/locales/en.json

@@ -199,7 +199,14 @@
         "claudeCodeFound": "Claude Code gateway detected at {{baseUrl}} — import?",
         "codexDone": "Codex providers imported",
         "claudeCodeDone": "Claude Code provider imported",
-        "failed": "Import failed"
+        "failed": "Import failed",
+        "codexMenu": "Import from Codex",
+        "codexMenuDesc": "Read ~/.codex/config.toml",
+        "claudeCodeMenu": "Import from Claude Code",
+        "claudeCodeMenuDesc": "Read the signed-in Claude Code session",
+        "customMenu": "Custom provider",
+        "customMenuDesc": "Enter API key and URL manually",
+        "alreadyImported": "Already imported"
       },
       "modal": {
         "title": "Add provider",

packages/i18n/src/locales/zh-CN.json

@@ -203,7 +203,14 @@
         "claudeCodeFound": "发现 Claude Code 网关 {{baseUrl}} — 导入？",
         "codexDone": "已导入 Codex 服务",
         "claudeCodeDone": "已导入 Claude Code 服务",
-        "failed": "导入失败"
+        "failed": "导入失败",
+        "codexMenu": "从 Codex 导入",
+        "codexMenuDesc": "读取 ~/.codex/config.toml",
+        "claudeCodeMenu": "从 Claude Code 导入",
+        "claudeCodeMenuDesc": "读取已登录的 Claude Code 会话",
+        "customMenu": "自定义服务",
+        "customMenuDesc": "手动填写 API key 和 URL",
+        "alreadyImported": "已导入"
       },
       "modal": {
         "title": "添加服务",