feat: add affiliate invite rebate flow and admin rebate-rate setting

backend/internal/handler/admin/setting_handler.go

@@ -185,6 +185,7 @@ func (h *SettingHandler) GetSettings(c *gin.Context) {
 		CustomEndpoints:                        dto.ParseCustomEndpoints(settings.CustomEndpoints),
 		DefaultConcurrency:                     settings.DefaultConcurrency,
 		DefaultBalance:                         settings.DefaultBalance,
+		AffiliateRebateRate:                    settings.AffiliateRebateRate,
 		DefaultUserRPMLimit:                    settings.DefaultUserRPMLimit,
 		DefaultSubscriptions:                   defaultSubscriptions,
 		EnableModelFallback:                    settings.EnableModelFallback,
@@ -338,6 +339,7 @@ type UpdateSettingsRequest struct {
 	// 默认配置
 	DefaultConcurrency                       int                               `json:"default_concurrency"`
 	DefaultBalance                           float64                           `json:"default_balance"`
+	AffiliateRebateRate                      *float64                          `json:"affiliate_rebate_rate"`
 	DefaultUserRPMLimit                      int                               `json:"default_user_rpm_limit"`
 	DefaultSubscriptions                     []dto.DefaultSubscriptionSetting  `json:"default_subscriptions"`
 	AuthSourceDefaultEmailBalance            *float64                          `json:"auth_source_default_email_balance"`
@@ -468,6 +470,16 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 	if req.DefaultBalance < 0 {
 		req.DefaultBalance = 0
 	}
+	affiliateRebateRate := previousSettings.AffiliateRebateRate
+	if req.AffiliateRebateRate != nil {
+		affiliateRebateRate = *req.AffiliateRebateRate
+	}
+	if affiliateRebateRate < service.AffiliateRebateRateMin {
+		affiliateRebateRate = service.AffiliateRebateRateMin
+	}
+	if affiliateRebateRate > service.AffiliateRebateRateMax {
+		affiliateRebateRate = service.AffiliateRebateRateMax
+	}
 	// 通用表格配置：兼容旧客户端未传字段时保留当前值。
 	if req.TableDefaultPageSize <= 0 {
 		req.TableDefaultPageSize = previousSettings.TableDefaultPageSize
@@ -1119,6 +1131,7 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 		CustomEndpoints:                  customEndpointsJSON,
 		DefaultConcurrency:               req.DefaultConcurrency,
 		DefaultBalance:                   req.DefaultBalance,
+		AffiliateRebateRate:              affiliateRebateRate,
 		DefaultUserRPMLimit:              req.DefaultUserRPMLimit,
 		DefaultSubscriptions:             defaultSubscriptions,
 		EnableModelFallback:              req.EnableModelFallback,
@@ -1433,6 +1446,7 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 		CustomEndpoints:                        dto.ParseCustomEndpoints(updatedSettings.CustomEndpoints),
 		DefaultConcurrency:                     updatedSettings.DefaultConcurrency,
 		DefaultBalance:                         updatedSettings.DefaultBalance,
+		AffiliateRebateRate:                    updatedSettings.AffiliateRebateRate,
 		DefaultUserRPMLimit:                    updatedSettings.DefaultUserRPMLimit,
 		DefaultSubscriptions:                   updatedDefaultSubscriptions,
 		EnableModelFallback:                    updatedSettings.EnableModelFallback,
@@ -1738,6 +1752,9 @@ func diffSettings(before *service.SystemSettings, after *service.SystemSettings,
 	if before.DefaultBalance != after.DefaultBalance {
 		changed = append(changed, "default_balance")
 	}
+	if before.AffiliateRebateRate != after.AffiliateRebateRate {
+		changed = append(changed, "affiliate_rebate_rate")
+	}
 	if !equalDefaultSubscriptions(before.DefaultSubscriptions, after.DefaultSubscriptions) {
 		changed = append(changed, "default_subscriptions")
 	}