refactor: extract migration constants

internal/constant/migrate.go

@@ -0,0 +1,21 @@
+package constant
+
+const (
+	// IDSchemaSignature 数据库表结构指纹的固定 ID
+	IDSchemaSignature = "sys_schema_sig"
+
+	// KeySchemaSignature 数据库表结构指纹，用于判断是否需要全量自动建表
+	KeySchemaSignature = "schema_signature"
+	
+	// KeyTaskEnvsMigrated 任务环境变量迁移标记 (v2版本强制重跑过)
+	KeyTaskEnvsMigrated = "task_envs_migrated_v2"
+	
+	// KeyTaskTagsMigrated 任务标签迁移标记 (v2版本强制重跑过)
+	KeyTaskTagsMigrated = "task_tags_migrated_v2"
+
+	// 以下是旧表或字段名，用于前置结构迁移时重命名或删除
+	TableMigrateQlTokens        = "ql_tokens"
+	ColumnMigrateQlTokenCode    = "code"
+	ColumnMigrateQlTokenToken   = "token"
+	ColumnMigrateDependencyType = "type"
+)