feat(distribution): 补齐退款加价回退、本站自卖与开通默认规则

退款时压缩卖方加价，人工/自动批次仅完结单可入账，号主收入进主站钱包；仲裁后重算释放并支持作废未入账 DS。开通时四种模式按默认生效，对外口径合并为 35/40/25，不再单独展示通道费。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/internal/modules/distribution/auth_onboard_test.go

@@ -19,16 +19,13 @@ func TestOnboardSiteAndLoginFlow(t *testing.T) {
 
 	// 1. Onboard new site
 	req := OnboardSiteRequest{
-		SiteCode:                "gz_dist",
-		SiteName:                "广州分销站",
-		Domain:                  "gz.distribution.com",
-		AdminUsername:           "gz_operator",
-		AdminPassword:           "Password123!",
-		AdminNickname:           "广州运营小李",
-		MemberType:              "operator",
-		DistributorReceiveRatio: 3.8,
-		PlatformSellRatio:       4.2,
-		ServiceFeeValue:         2.0,
+		SiteCode:      "gz_dist",
+		SiteName:      "广州分销站",
+		Domain:        "gz.distribution.com",
+		AdminUsername: "gz_operator",
+		AdminPassword: "Password123!",
+		AdminNickname: "广州运营小李",
+		MemberType:    "operator",
 	}
 
 	resp, err := svc.OnboardSite(ctx, req)
@@ -48,11 +45,11 @@ func TestOnboardSiteAndLoginFlow(t *testing.T) {
 	if resp.Member.SiteID == nil || *resp.Member.SiteID != resp.Site.ID {
 		t.Fatalf("expected SiteID=%d, got %v", resp.Site.ID, resp.Member.SiteID)
 	}
-	if resp.Rule.DistributorReceiveRatio != 38 {
-		t.Fatalf("expected rule percent 38, got %f", resp.Rule.DistributorReceiveRatio)
+	if resp.Rule.DistributorReceiveRatio != 35 || resp.Rule.PlatformSellRatio != 40 || resp.Rule.ServiceFeeValue != 25 {
+		t.Fatalf("expected default 35/40/25, got %+v", resp.Rule)
 	}
-	if resp.Rule.Status != "draft" {
-		t.Fatalf("onboard rule must stay draft until split is verified, got %s", resp.Rule.Status)
+	if resp.Rule.Status != "active" {
+		t.Fatalf("onboard rules should be active by default, got %s", resp.Rule.Status)
 	}
 
 	// 2. Duplicate site code or domain check