feat: 帖子收藏与用户关注

- 新增收藏功能：favorite 服务与 handler、FavoriteButton 组件
- 新增关注功能：follow 服务与 handler、FollowButton 组件
- 用户主页适配关注/粉丝与收藏展示
- flash 消息工具、广告与侧边栏组件微调

backend/router/router.go

@@ -66,6 +66,8 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 	commentSvc := service.NewCommentService(model.DB).WithSetting(settingSvc)
 	likeSvc := service.NewLikeService(model.DB)
 	notifSvc := service.NewNotificationService(model.DB)
+	favoriteSvc := service.NewFavoriteService(model.DB).WithPosts(postSvc)
+	followSvc := service.NewFollowService(model.DB).WithNotification(notifSvc)
 	overviewSvc := service.NewOverviewService(model.DB)
 	checkinSvc := service.NewCheckinService(model.DB).WithSetting(settingSvc)
 	announcementSvc := service.NewAnnouncementService(model.DB)
@@ -108,6 +110,8 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		Post:         postSvc,
 		Comment:      commentSvc,
 		Like:         likeSvc,
+		Favorite:     favoriteSvc,
+		Follow:       followSvc,
 		Notification: notifSvc,
 		OverviewSvc:  overviewSvc,
 		Checkin:      checkinSvc,
@@ -170,8 +174,11 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		pubAPI.POST("/posts/:id/unlock-password", middleware.CSRFMiddleware(), middleware.RateLimitMiddleware(limiter, service.RateHidePassword), h.UnlockPostPassword)
 		pubAPI.GET("/posts/:id/attachments/:aid/download", h.DownloadPostAttachment)
 		pubAPI.GET("/posts/:id/comments", h.PostComments)
+		pubAPI.GET("/posts/:id/comments/:cid", h.CommentLocation)
 		pubAPI.GET("/users/:id", h.UserProfile)
 		pubAPI.GET("/users/:id/comments", h.UserComments)
+		pubAPI.GET("/users/:id/favorites", h.UserFavorites)
+		pubAPI.GET("/users/:id/following", h.UserFollowing)
 		pubAPI.GET("/announcements", h.AnnouncementsList)
 		pubAPI.GET("/announcements/:id", h.AnnouncementDetail)
 		pubAPI.GET("/pages", h.SitePagesList)
@@ -220,6 +227,8 @@ func Setup(cfg *config.Config) (*gin.Engine, error) {
 		api.PUT("/posts/:id/recommend", h.ToggleRecommend)
 		api.PUT("/posts/:id/lock", h.TogglePostLock)
 		api.POST("/posts/:id/like", h.ToggleLike)
+		api.POST("/posts/:id/favorite", middleware.StaffExempt(middleware.RateLimitUserMiddleware(limiter, service.RateInteract)), h.ToggleFavorite)
+		api.POST("/users/:id/follow", middleware.StaffExempt(middleware.RateLimitUserMiddleware(limiter, service.RateInteract)), h.ToggleFollow)
 		api.POST("/posts/:id/comments", middleware.StaffExempt(middleware.RateLimitMiddleware(limiter, service.RateComment)), h.CreateComment)
 		api.PUT("/posts/:id/comments/:cid", middleware.StaffExempt(middleware.RateLimitMiddleware(limiter, service.RateComment)), h.UpdateComment)
 		api.DELETE("/posts/:id/comments/:cid", h.DeleteComment)