feat: stat 新增按游戏统计充值净额接口 GetGamePayAmount

对接 stat.gaore.com 的 /pay/getGamePayAmount：
- pay_channel.go：GetGamePayAmountReq/Resp/Param + 工厂函数(POST form，
  入参 tdate/tdate2/game_id/group_by_date)，返回 game_id + pay_amount(单位元)；
- client.go：新增 GetGamePayAmount 方法；
- client_test.go：新增 TestGetGamePayAmount。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

services/stat/client.go

@@ -157,3 +157,10 @@ func (c *Client) CallbackWeightUpdate(req *CallbackWeightUpdateReq) (resp *Callb
 	err = c.DoAction(req, resp)
 	return
 }
+
+// GetGamePayAmount 按游戏统计充值净额(gr_pay_channel.pay_amount)
+func (c *Client) GetGamePayAmount(req *GetGamePayAmountReq) (resp *GetGamePayAmountResp, err error) {
+	resp = CreateGetGamePayAmountResp()
+	err = c.DoAction(req, resp)
+	return
+}

services/stat/client_test.go

@@ -350,3 +350,31 @@ func TestCallbackWeightUpdate(t *testing.T) {
 	}
 	t.Log(resp)
 }
+
+// TestGetGamePayAmount 按游戏统计充值净额（pay_amount，单位元）
+func TestGetGamePayAmount(t *testing.T) {
+	client, err := NewClient()
+	if err != nil {
+		t.Fatal(err)
+	}
+	req := CreateGetGamePayAmountReq(GetGamePayAmountParam{
+		Tdate:       "2026-05-01",        // 开始日期
+		Tdate2:      "2026-05-31",        // 结束日期（含当天）
+		GameIds:     []int64{3706},       // 游戏id(=switch_game_id)，传 nil 则全部
+		GroupByDate: false,               // 仅按游戏汇总；true 则按日期+游戏拆分
+	})
+
+	resp, err := client.GetGamePayAmount(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fmt.Println(resp.Code, resp.Msg)
+	for _, r := range resp.Data.List {
+		fmt.Printf("tdate=%s game_id=%d pay_amount=%.2f\n", r.Tdate, r.GameId, r.PayAmount)
+	}
+
+	// 成功码为 1
+	if resp.Code != 1 {
+		t.Errorf("GetGamePayAmount failed: code=%d msg=%s", resp.Code, resp.Msg)
+	}
+}

services/stat/pay_channel.go

@@ -0,0 +1,73 @@
+package stat
+
+import (
+	"strconv"
+	"strings"
+
+	"golib.gaore.com/GaoreGo/gaore-common-sdk-go/sdk/requests"
+	"golib.gaore.com/GaoreGo/gaore-common-sdk-go/sdk/responses"
+)
+
+// GetGamePayAmountReq 按游戏统计充值净额(gr_pay_channel.pay_amount)请求
+type GetGamePayAmountReq struct {
+	*requests.RpcRequest
+}
+
+// GetGamePayAmountParam 调用参数
+type GetGamePayAmountParam struct {
+	Tdate       string  // 开始日期 YYYY-MM-DD（必填）
+	Tdate2      string  // 结束日期 YYYY-MM-DD（选填，含当天）
+	GameIds     []int64 // 游戏id（选填，空=全部游戏）
+	GroupByDate bool    // true=按日期+游戏分组；false=仅按游戏汇总
+}
+
+// GetGamePayAmountResp 响应
+type GetGamePayAmountResp struct {
+	*responses.BaseResponse
+	Code int               `json:"code"`
+	Msg  string            `json:"msg"`
+	Data GamePayAmountList `json:"data"`
+}
+
+type GamePayAmountList struct {
+	List []GamePayAmount `json:"list"`
+}
+
+// GamePayAmount 单条统计；未按日期分组时 Tdate 为空
+type GamePayAmount struct {
+	Tdate     string  `json:"tdate"`
+	GameId    int64   `json:"game_id"`
+	PayAmount float64 `json:"pay_amount"` // 充值净额，单位：元
+}
+
+// CreateGetGamePayAmountReq 创建「按游戏统计充值净额」请求
+func CreateGetGamePayAmountReq(param GetGamePayAmountParam) *GetGamePayAmountReq {
+	req := &GetGamePayAmountReq{
+		&requests.RpcRequest{},
+	}
+	req.InitWithApiInfo(HOST, VERSION, "/pay/getGamePayAmount")
+	req.Method = requests.POST
+
+	gameIds := make([]string, 0, len(param.GameIds))
+	for _, id := range param.GameIds {
+		gameIds = append(gameIds, strconv.FormatInt(id, 10))
+	}
+	groupByDate := "0"
+	if param.GroupByDate {
+		groupByDate = "1"
+	}
+	req.FormParams = map[string]string{
+		"tdate":         param.Tdate,
+		"tdate2":        param.Tdate2,
+		"game_id":       strings.Join(gameIds, ","),
+		"group_by_date": groupByDate,
+	}
+	return req
+}
+
+// CreateGetGamePayAmountResp 创建响应对象
+func CreateGetGamePayAmountResp() *GetGamePayAmountResp {
+	return &GetGamePayAmountResp{
+		BaseResponse: &responses.BaseResponse{},
+	}
+}