feat(admin): 独立后台壳、站点分析与聊天监管，公开站拆出主题切换与访问埋点

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

backend/model/db.go

@@ -37,7 +37,7 @@ func InitDB(dsn string) error {
 
 	if err := db.AutoMigrate(
 		&User{}, &Board{}, &Post{}, &Comment{}, &CommentEditHistory{}, &RefreshToken{}, &Like{}, &Notification{}, &Checkin{},
-		&Announcement{}, &SiteSetting{}, &Attachment{}, &UserBoard{}, &LoginLog{},
+		&Announcement{}, &SiteSetting{}, &SiteDailyStats{}, &SiteDailyVisitor{}, &Attachment{}, &UserBoard{}, &LoginLog{},
 		&ChatRoom{}, &ChatRoomMember{}, &ChatMessage{},
 		&PointLedger{}, &PostContentUnlock{}, &PostAttachment{}, &PostAttachmentUnlock{},
 		&PostPollVote{}, &PostLotteryEntry{},