chore(init): 初始化解忧商行项目并完成 Phase 0 基座

backend/internal/model/chat_quick_reply.go

@@ -0,0 +1,17 @@
+package model
+
+import "time"
+
+type ChatQuickReply struct {
+	ID          uint64    `gorm:"primaryKey;autoIncrement" json:"id"`
+	AdminUserID uint64    `gorm:"not null;default:0;index" json:"admin_user_id"` // 0=全局, >0=个人
+	Title       string    `gorm:"size:64;not null" json:"title"`
+	Content     string    `gorm:"type:text;not null" json:"content"`
+	SortOrder   int       `gorm:"not null;default:0" json:"sort_order"`
+	CreatedAt   time.Time `gorm:"not null;default:CURRENT_TIMESTAMP" json:"created_at"`
+	UpdatedAt   time.Time `gorm:"not null;default:CURRENT_TIMESTAMP" json:"updated_at"`
+}
+
+func (ChatQuickReply) TableName() string {
+	return "chat_quick_replies"
+}