feat: add ads/sponsor/captcha modules and polish home & chat UI

backend/model/ad.go

@@ -0,0 +1,44 @@
+package model
+
+import (
+	"time"
+
+	"gorm.io/gorm"
+)
+
+// 广告类型与状态
+const (
+	AdKindImage = "image"
+	AdKindText  = "text"
+
+	AdStatusPending  = "pending"
+	AdStatusActive   = "active"
+	AdStatusRejected = "rejected"
+	AdStatusExpired  = "expired"
+)
+
+// Ad 赞助广告（游客可申购，管理员审核后展示于首页侧栏）
+type Ad struct {
+	ID            uint           `gorm:"primaryKey" json:"id"`
+	Kind          string         `gorm:"size:16;not null;index" json:"kind"`     // image | text
+	Status        string         `gorm:"size:16;not null;index" json:"status"`   // pending/active/rejected/expired
+	ContactEmail  string         `gorm:"size:128;not null" json:"contact_email"`
+	LinkURL       string         `gorm:"size:512;not null" json:"link_url"`
+	ImageURL      string         `gorm:"size:512" json:"image_url"` // 图片广告
+	Title         string         `gorm:"size:64" json:"title"`      // 文字广告
+	TextColor     string         `gorm:"size:16" json:"text_color"`
+	BgColor       string         `gorm:"size:16" json:"bg_color"`
+	DurationDays  int            `gorm:"not null" json:"duration_days"`
+	PaymentID     string         `gorm:"size:64;not null" json:"payment_id"`
+	BuyerNote     string         `gorm:"size:200" json:"buyer_note"`
+	StartsAt      *time.Time     `json:"starts_at"`
+	EndsAt        *time.Time     `json:"ends_at"`
+	RejectReason  string         `gorm:"size:200" json:"reject_reason"`
+	SortOrder     int            `gorm:"not null;default:0" json:"sort_order"`
+	SubmitIP      string         `gorm:"size:45" json:"-"`
+	ReviewedAt    *time.Time     `json:"reviewed_at"`
+	ReviewedBy    *uint          `json:"reviewed_by"`
+	CreatedAt     time.Time      `json:"created_at"`
+	UpdatedAt     time.Time      `json:"updated_at"`
+	DeletedAt     gorm.DeletedAt `gorm:"index" json:"-"`
+}

backend/model/db.go

@@ -61,7 +61,7 @@ func InitDB(dsn string) error {
 		&Announcement{}, &SitePage{}, &SiteSetting{}, &SiteDailyStats{}, &SiteDailyVisitor{}, &Attachment{}, &UserBoard{}, &LoginLog{},
 		&ChatRoom{}, &ChatRoomMember{}, &ChatMessage{},
 		&PointLedger{}, &PostContentUnlock{}, &PostAttachment{}, &PostAttachmentUnlock{},
-		&PostPollVote{}, &PostLotteryEntry{},
+		&PostPollVote{}, &PostLotteryEntry{}, &Ad{},
 	); err != nil {
 		return fmt.Errorf("自动迁移失败: %w", err)
 	}
@@ -78,6 +78,11 @@ func InitDB(dsn string) error {
 		return fmt.Errorf("login_logs 默认值修正失败: %w", err)
 	}
 
+	// 早期 site_settings.value 可能是 varchar(255)；广告/赞助商 JSON 会超长
+	if err := prepareSiteSettingValueText(db); err != nil {
+		return fmt.Errorf("site_settings.value 扩容失败: %w", err)
+	}
+
 	// 新表结构就位后删除遗留的明文列
 	if err := dropLegacyRefreshTokenColumn(db); err != nil {
 		return fmt.Errorf("refresh token 旧列清理失败: %w", err)
@@ -152,6 +157,28 @@ func prepareAnnouncementPinnedColumn(db *gorm.DB) error {
 	return db.Exec(`ALTER TABLE announcements ADD COLUMN pinned boolean NOT NULL DEFAULT false`).Error
 }
 
+// prepareSiteSettingValueText 将 site_settings.value 从 varchar(255) 扩为 text（幂等）
+func prepareSiteSettingValueText(db *gorm.DB) error {
+	var tableCount int64
+	if err := db.Raw(`SELECT count(1) FROM information_schema.tables WHERE table_name = 'site_settings'`).
+		Scan(&tableCount).Error; err != nil {
+		return err
+	}
+	if tableCount == 0 {
+		return nil
+	}
+	var dataType string
+	if err := db.Raw(`SELECT data_type FROM information_schema.columns
+		WHERE table_name = 'site_settings' AND column_name = 'value'`).
+		Scan(&dataType).Error; err != nil {
+		return err
+	}
+	if dataType == "" || dataType == "text" {
+		return nil
+	}
+	return db.Exec(`ALTER TABLE site_settings ALTER COLUMN value TYPE text`).Error
+}
+
 // prepareRefreshTokenSessionColumns 存量 refresh_tokens 加 logged_in_at / last_used_at：
 // 先可空加列，用 created_at 回填后再收紧 NOT NULL。
 func prepareRefreshTokenSessionColumns(db *gorm.DB) error {