feat(distribution): 分站可下调收号比例且不超过主站上限

让分销站能按自身能力下调收号比例扩大利润，同时把主站回收比例作为硬边界，避免分站把比例加得比主站更高。

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

backend/internal/modules/distribution/repository_test.go

@@ -1,6 +1,7 @@
 package distribution
 
 import (
+	"encoding/json"
 	"errors"
 	"testing"
 	"time"
@@ -8,6 +9,7 @@ import (
 	"hfb_sys/backend/internal/database"
 	"hfb_sys/backend/internal/model"
 
+	"gorm.io/datatypes"
 	"gorm.io/gorm"
 )
 
@@ -666,7 +668,19 @@ func TestDistributionBrandingAndMarkup(t *testing.T) {
 		t.Fatalf("cleared listing_qrcode_url = %q, want empty", qrCleared.ListingQrcodeURL)
 	}
 
-	// Verify PublicSiteInfo contains branding
+	delta := 3.5
+	ratioUpdated, err := repo.UpdateSite(t.Context(), 0, site.ID, UpdateSiteRequest{ReceiveRatioDelta: &delta})
+	if err != nil {
+		t.Fatalf("UpdateSite receive ratio failed: %v", err)
+	}
+	if ratioUpdated.ReceiveRatioDelta != 3.5 {
+		t.Fatalf("receive_ratio_delta = %v, want 3.5", ratioUpdated.ReceiveRatioDelta)
+	}
+	negative := -1.0
+	if _, err := repo.UpdateSite(t.Context(), 0, site.ID, UpdateSiteRequest{ReceiveRatioDelta: &negative}); !errors.Is(err, ErrInvalidAmount) {
+		t.Fatalf("negative receive ratio err = %v, want ErrInvalidAmount", err)
+	}
+
 	pubInfo, err := repo.GetPublicSiteInfo(t.Context(), "brand_site", "")
 	if err != nil {
 		t.Fatalf("GetPublicSiteInfo failed: %v", err)
@@ -674,6 +688,9 @@ func TestDistributionBrandingAndMarkup(t *testing.T) {
 	if pubInfo.LogoURL != "https://cdn.example.com/logo.png" {
 		t.Fatalf("expected LogoURL, got: %+v", pubInfo)
 	}
+	if pubInfo.ReceiveRatioDelta != 3.5 {
+		t.Fatalf("public receive_ratio_delta = %v, want 3.5", pubInfo.ReceiveRatioDelta)
+	}
 
 	faviconOnly := "https://cdn.example.com/favicon2.ico"
 	partial, err := repo.UpdateSiteBranding(t.Context(), 0, site.ID, UpdateSiteBrandingRequest{FaviconURL: &faviconOnly})
@@ -746,12 +763,24 @@ func TestDistributionReceivedListingsAndWallet(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	summary, err := json.Marshal(map[string]any{
+		"price_breakdown": map[string]any{
+			"seller_ratio":       43.0,
+			"seller_total_price": 232.6,
+			"buyer_ratio":        38.0,
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
 	ga := model.GameAccount{
 		OwnerID:       user.ID,
 		GameName:      "delta_force",
 		ServerRegion:  "cn",
 		LoginPlatform: "pc",
 		Title:         "满配三角洲账号",
+		HafCoinAmount: 100_000_000,
+		AssetSummary:  datatypes.JSON(summary),
 	}
 	if err := db.Create(&ga).Error; err != nil {
 		t.Fatal(err)
@@ -786,6 +815,9 @@ func TestDistributionReceivedListingsAndWallet(t *testing.T) {
 	if item.ListingNo != "RL-99001" || item.GameName != "delta_force" || item.OwnerNickname != "seller01" {
 		t.Fatalf("unexpected received listing: %+v", item)
 	}
+	if item.SellerRatio != 43 || item.SellerTotalPriceCent != 23260 || item.BuyerRatio != 38 {
+		t.Fatalf("expected main-site receive pricing, got ratio=%v price=%d buyer=%v", item.SellerRatio, item.SellerTotalPriceCent, item.BuyerRatio)
+	}
 
 	if err := repo.UpdateReceivedListingStatus(t.Context(), 0, listing.ID, "inactive"); !errors.Is(err, ErrInvalidListingStatus) {
 		t.Fatalf("inactive status err = %v", err)