feat(distribution): 分销站点增加用户数量统计与用户信息展示模块

- 数据模型与迁移: 新增 000082 迁移在 users 表追加 distribution_site_id 并建索引，用户首次在分销站点注册/短信登录时自动绑定站点归属
- 分销管理接口: 新增 GET /admin/distribution/users 接口，聚合本站注册用户与下单客户，返回完整11位手机号、累计消费金额、订单数及来源标签
- 统计与大盘扩展: GET /admin/distribution/sites/:id/analytics 补全今日注册、累计用户、成交客户指标，主站分销商列表追加用户体量展示
- 分销后台前端: 新增「客户与用户」页面 (Users.tsx) 支持一键复制手机号与订单穿透，大盘 (Dashboard.tsx) 增加用户规模核心卡片
- 自动化测试与门禁: 新增 TestListDistributionUsersAndAnalytics 单元测试，通过全量 Go 后端集成测试及前后端构建检查

backend/internal/router/router.go

@@ -735,6 +735,7 @@ func New(cfg config.Config, deps Dependencies, logger *zap.Logger) *gin.Engine {
 			adminRoutes.POST("/distribution/sites/:id/qrcodes/batch-delete", requirePerm("qrcode:manage"), chatHandler.BatchDeleteSiteQrCodeHandler)
 			adminRoutes.PATCH("/distribution/sites/:id/qrcodes/:qrcodeId", requirePerm("qrcode:manage"), chatHandler.UpdateSiteQrCodeHandler)
 			adminRoutes.DELETE("/distribution/sites/:id/qrcodes/:qrcodeId", requirePerm("qrcode:manage"), chatHandler.DeleteSiteQrCodeHandler)
+			adminRoutes.GET("/distribution/users", requirePerm("distribution:site_view"), distributionHandler.ListDistributionUsers)
 			adminRoutes.GET("/distribution/received-listings", requirePerm("distribution:account_view"), distributionHandler.ListReceivedListings)
 			adminRoutes.PUT("/distribution/received-listings/:id/status", requirePerm("distribution:account_display"), distributionHandler.UpdateReceivedListingStatus)
 			adminRoutes.GET("/distribution/announcements", requirePerm("distribution:announcement_view"), distributionHandler.ListSiteAnnouncements)