feat(osi): 体检最近一次查询打通（T-301）

- osi.LastHealthCheck（JKTJLSJL00002 /auto/jktjlscx/query）
- contract.HealthCheckSummary 只强类型化定位字段，完整内容走 Result.Raw
- codes.go 登记 JKTJLSJL00002 + JKTJLIST00002 路由
- 单测：路径/解码/Raw 保留/idcard 小写映射/单键校验（脱敏假数据）
- 实测：单查 JKTJ00002 平台未部署；data 为单对象；身份证字段小写 idcard

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

osi/jktj.go

@@ -0,0 +1,34 @@
+package osi
+
+import (
+	"context"
+
+	"chis_osi/contract"
+)
+
+type FindHealthCheckQuery struct {
+	IDCard string
+	PHRID  string
+	EMPIID string
+}
+
+// LastHealthCheck 查询某人最近一次体检（JKTJLSJL00002 /auto/jktjlscx/query）。
+// data 为单个体检对象（非数组）；summary 只取定位字段，完整内容见返回的 Result.Raw。
+func (c *Client) LastHealthCheck(ctx context.Context, query FindHealthCheckQuery) (contract.HealthCheckSummary, Result, error) {
+	baseInfo, err := query.baseInfo()
+	if err != nil {
+		return contract.HealthCheckSummary{}, Result{}, err
+	}
+	var summary contract.HealthCheckSummary
+	result, err := c.Call(ctx, ServiceIDJKTJLast, baseInfo, &summary)
+	return summary, result, err
+}
+
+func (q FindHealthCheckQuery) baseInfo() (map[string]string, error) {
+	fields := []queryField{
+		{name: "idCard", value: q.IDCard},
+		{name: "empiId", value: q.EMPIID},
+		{name: "phrid", value: q.PHRID},
+	}
+	return singleBaseInfo("last health check", fields)
+}