## MODIFIED Requirements

### Requirement: ping detail 摘要
系统 SHALL 在 ping API 序列化时从 observation 动态生成结构化 detail 摘要，展示关键指标。API registry type SHALL 仍为 `ping`。

#### Scenario: 目标可达无丢包
- **WHEN** ping observation 为 alive=true, avgLatencyMs=12, packetLoss=0%, transmitted=3, received=3
- **THEN** detail SHALL 为 `alive, avg 12ms, loss 0% (3/3)`

#### Scenario: 目标可达有丢包
- **WHEN** ping observation 为 alive=true, avgLatencyMs=156, maxLatencyMs=340, packetLoss=33%, transmitted=3, received=2
- **THEN** detail SHALL 包含 avg、max 和 loss 信息

#### Scenario: 目标不可达
- **WHEN** ping observation 为 alive=false, transmitted=3, received=0
- **THEN** detail SHALL 为 `unreachable (0/3 received)`