ar-player bootstrap ready

Phase13 着手前の基盤確認ページです。現時点では入口整備とデータ配置確認のみを扱います。

{
    "status": "ok",
    "module": "ar-player",
    "environment": "prod",
    "request_path": "/",
    "database": {
        "configured": true,
        "connected": true,
        "database": "kumorarika_prod",
        "error": null
    },
    "php_version": "8.3.21",
    "app_root": "/home/kumorarika/kumorarika.com/app",
    "project_root": "/home/kumorarika/kumorarika.com",
    "timestamp": "2026-04-11T15:10:55+09:00"
}