sequenceDiagram
    participant U as 用户浏览器
    participant G as Gin Router
    participant H as HomeHandler
    participant CM as CardModel
    participant SM as SettingModel
    participant T as html/template

    U->>G: GET /
    G->>H: HomeHandler(c)
    H->>CM: GetEnabledCards()
    CM->>CM: SELECT * FROM cards WHERE enabled=1 ORDER BY sort
    CM-->>H: []Card
    H->>SM: GetSetting("search_engine")
    SM->>SM: SELECT value FROM settings WHERE key='search_engine'
    SM-->>H: search URL template
    H->>T: ExecuteTemplate("home.html", data)
    T-->>U: HTML (搜索框 + 卡片网格)