feat(wren-ai-service): prompt enhancement to focus on localization language

[paopa]

Changes

• Enhanced question recommendation pipeline to fully localize both questions and category names

Before & After Example

// Before
{
  "question": "在 Wren AI Cloud 平台中，有多少用戶的電子郵件已經驗證？",
  "category": "user_profile"
}

// After
{
  "question": "在過去一年中，多少用戶的電子郵件已經驗證？",
  "category": "用戶資料"
}

[cyyeh]

LGTM