feat(distribution): 支持分站发布群固定二维码

主站分销配置可为每个站点绑定可复用企微码，号主在该站上传账号后发到对应发布群，不再消耗主站码池。

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

backend/internal/modules/distribution/dto.go

@@ -15,6 +15,7 @@ type SiteDTO struct {
 	AnnouncementsJSON     string    `json:"announcements_json"`
 	FooterInfoJSON        string    `json:"footer_info_json"`
 	DefaultSupportGroupID *uint64   `json:"default_support_group_id,omitempty"`
+	ListingQrcodeURL      string    `json:"listing_qrcode_url"`
 	TaxEnabled            bool      `json:"tax_enabled"`
 	TaxRateBPS            int64     `json:"tax_rate_bps"`
 	SettlementHoldDays    int       `json:"settlement_hold_days"`
@@ -28,6 +29,7 @@ type CreateSiteRequest struct {
 	Domain                string  `json:"domain" binding:"required,max=255"`
 	DisplayAccountEnabled *bool   `json:"display_account_enabled"`
 	DefaultSupportGroupID *uint64 `json:"default_support_group_id"`
+	ListingQrcodeURL      *string `json:"listing_qrcode_url"`
 	TaxEnabled            *bool   `json:"tax_enabled"`
 	TaxRateBPS            *int64  `json:"tax_rate_bps"`
 	SettlementHoldDays    *int    `json:"settlement_hold_days"`
@@ -39,6 +41,7 @@ type UpdateSiteRequest struct {
 	Status                *string `json:"status"`
 	DisplayAccountEnabled *bool   `json:"display_account_enabled"`
 	DefaultSupportGroupID *uint64 `json:"default_support_group_id"`
+	ListingQrcodeURL      *string `json:"listing_qrcode_url"`
 	TaxEnabled            *bool   `json:"tax_enabled"`
 	TaxRateBPS            *int64  `json:"tax_rate_bps"`
 	SettlementHoldDays    *int    `json:"settlement_hold_days"`

backend/internal/modules/distribution/repository.go

@@ -253,6 +253,9 @@ func (r *Repository) CreateSite(ctx context.Context, req CreateSiteRequest) (*Si
 	if req.DefaultSupportGroupID != nil {
 		row.DefaultSupportGroupID = req.DefaultSupportGroupID
 	}
+	if req.ListingQrcodeURL != nil {
+		row.ListingQrcodeURL = strings.TrimSpace(*req.ListingQrcodeURL)
+	}
 	if req.TaxEnabled != nil {
 		row.TaxEnabled = *req.TaxEnabled
 	}
@@ -305,6 +308,9 @@ func (r *Repository) UpdateSite(ctx context.Context, adminID, id uint64, req Upd
 		if req.DefaultSupportGroupID != nil {
 			row.DefaultSupportGroupID = req.DefaultSupportGroupID
 		}
+		if req.ListingQrcodeURL != nil {
+			row.ListingQrcodeURL = strings.TrimSpace(*req.ListingQrcodeURL)
+		}
 		if req.TaxEnabled != nil {
 			row.TaxEnabled = *req.TaxEnabled
 		}
@@ -467,6 +473,7 @@ func siteDTO(row model.DistributionSite) SiteDTO {
 		Status:                row.Status,
 		DisplayAccountEnabled: row.DisplayAccountEnabled,
 		DefaultSupportGroupID: row.DefaultSupportGroupID,
+		ListingQrcodeURL:      row.ListingQrcodeURL,
 		TaxEnabled:            row.TaxEnabled,
 		TaxRateBPS:            row.TaxRateBPS,
 		SettlementHoldDays:    row.SettlementHoldDays,

backend/internal/modules/distribution/repository_test.go

@@ -649,6 +649,23 @@ func TestDistributionBrandingAndMarkup(t *testing.T) {
 		t.Fatalf("unexpected branding: %+v", updated)
 	}
 
+	qrURL := "/api/files/object?key=qrcode/brand-site.png"
+	qrUpdated, err := repo.UpdateSite(t.Context(), 0, site.ID, UpdateSiteRequest{ListingQrcodeURL: &qrURL})
+	if err != nil {
+		t.Fatalf("UpdateSite listing qrcode failed: %v", err)
+	}
+	if qrUpdated.ListingQrcodeURL != qrURL {
+		t.Fatalf("listing_qrcode_url = %q, want %q", qrUpdated.ListingQrcodeURL, qrURL)
+	}
+	cleared := ""
+	qrCleared, err := repo.UpdateSite(t.Context(), 0, site.ID, UpdateSiteRequest{ListingQrcodeURL: &cleared})
+	if err != nil {
+		t.Fatalf("clear listing qrcode failed: %v", err)
+	}
+	if qrCleared.ListingQrcodeURL != "" {
+		t.Fatalf("cleared listing_qrcode_url = %q, want empty", qrCleared.ListingQrcodeURL)
+	}
+
 	// Verify PublicSiteInfo contains branding
 	pubInfo, err := repo.GetPublicSiteInfo(t.Context(), "brand_site", "")
 	if err != nil {