sequenceDiagram
    autonumber
    participant FE as 前端页面
    participant API as admin.ts
    participant RT as FastAPI Router
    participant SVC as Service
    participant DB as PostgreSQL
    participant FS as 日志文件(RUNTIME_LOG_DIR)

    Note over FE,FS: A 配置变更历史（带筛选）
    FE->>API: getSystemLogs({config_key, changed_by, from, to, page, page_size})
    API->>RT: GET /api/admin/system-logs?...
    RT->>RT: require_admin()
    RT->>SVC: get_system_logs(db, filters)
    SVC->>DB: SELECT ConfigChangeLog WHERE ... ORDER changed_at DESC
    SVC->>DB: JOIN agents 取 changed_by_name
    DB-->>SVC: rows
    SVC-->>RT: {items, total, page, page_size}
    RT-->>FE: {code:0, data}

    Note over FE,FS: B 安全审计日志（复用后端）
    FE->>API: getAuditLogs({employee_id, action, resource, from, to, page, page_size})
    API->>RT: GET /api/admin/audit-logs?...
    RT->>RT: require_permission(audit_log:read:all)
    RT->>SVC: list_audit_logs(db, filters)
    SVC->>DB: SELECT AuditLog WHERE ...
    DB-->>SVC: rows
    SVC-->>RT: {items, total, page, page_size}
    RT-->>FE: {code:0, data}

    Note over FE,FS: D 运行期日志（列表）
    FE->>API: getRuntimeLogs({level, from, to, keyword, page, page_size})
    API->>RT: GET /api/admin/runtime-logs?...
    RT->>RT: require_admin()
    RT->>SVC: read_runtime_logs(RUNTIME_LOG_DIR, filters)
    SVC->>FS: 读 *.log 逐行 json.loads
    FS-->>SVC: 命中行
    SVC-->>RT: {items, total, page, page_size}
    RT-->>FE: {code:0, data}

    Note over FE,FS: D 运行期日志（下载）
    FE->>API: getRuntimeLogDownload({level, from, to, keyword})
    API->>RT: GET /api/admin/runtime-logs?download=true
    RT->>RT: require_admin()
    RT->>SVC: build_runtime_log_stream(RUNTIME_LOG_DIR, filters)
    SVC->>FS: 读 *.log 过滤行
    RT-->>FE: StreamingResponse(text/plain, attachment)