feat: fulfillment modes, MQ, admin status, docs; scrub compose secrets

Made-with: Cursor

mengyastore-backend-go/internal/database/models.go

@@ -50,6 +50,9 @@ type ProductRow struct {
 	TotalSold       int         `gorm:"default:0"`
 	ViewCount       int         `gorm:"default:0"`
 	DeliveryMode    string      `gorm:"size:20;default:'auto'"`
+	// FulfillmentType: card=卡密库存 / fixed=固定内容（不限库存，内容见 FixedContent）
+	FulfillmentType string      `gorm:"size:16;default:card;index"`
+	FixedContent    string      `gorm:"type:text"`
 	ShowNote        bool        `gorm:"default:true"`
 	ShowContact     bool        `gorm:"default:true"`
 	CreatedAt       time.Time   `gorm:"index"`