feat: 新增排行榜模块

- 新增 leaderboard 服务与 handler、前端排行榜页面
- 路由与首页入口适配

backend/router/router.go

@@ -75,6 +75,7 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 	uploadSvc.WithOperations(ops)
 	postFileSvc.WithOperations(ops)
 	pointsSvc := service.NewPointsService(model.DB)
+	leaderboardSvc := service.NewLeaderboardService(model.DB)
 	adminUserSvc := service.NewAdminUserService(model.DB)
 	legacyImportSvc := service.NewLegacyImportService(model.DB, filepath.Join(cfg.DataDir, "uploads"))
 	moderationSvc := service.NewModerationService(model.DB, notifSvc)
@@ -126,6 +127,7 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		Ads:          adSvc,
 		Sidebar:      service.NewSidebarService(model.DB),
 		Badge:        badgeSvc,
+		LeaderboardSvc: leaderboardSvc,
 	}
 	// 通知落库后统一推 WS 红点（点赞/评论/审核/@ 等共用）
 	notifSvc.OnNotifyNew = func(userID uint) {
@@ -175,6 +177,8 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		pubAPI.GET("/pages", h.SitePagesList)
 		pubAPI.GET("/pages/:slug", h.SitePageDetail)
 		pubAPI.GET("/settings", h.PublicSettings)
+		pubAPI.GET("/leaderboard", h.Leaderboard)
+		pubAPI.GET("/leaderboard/me", h.LeaderboardMe)
 		pubAPI.GET("/site-state", h.SiteState)
 		pubAPI.GET("/media/:object", h.PublicObject)
 		pubAPI.POST("/auth/code", middleware.CSRFMiddleware(), h.SendEmailCode)