[功能] 实现数据库版本管理与迁移逻辑，确保数据库结构与版本一致性

openflare_server/model/database_schema_version.go

@@ -0,0 +1,19 @@
+package model
+
+import "time"
+
+const (
+	legacyDatabaseSchemaVersion  = 1
+	currentDatabaseSchemaVersion = 2
+	databaseSchemaVersionRowID   = 1
+)
+
+type DatabaseSchemaVersion struct {
+	ID        uint      `json:"id" gorm:"primaryKey"`
+	Version   int       `json:"version" gorm:"not null"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
+func (DatabaseSchemaVersion) TableName() string {
+	return "database_schema_versions"
+}