fix: crypto TS类型修复 + EXPLAIN AST类型补充

dist/metona-sqlark.d.ts

@@ -185,6 +185,14 @@ interface IStorageEngine {
     commitTransaction(): Promise<void>;
     /** 回滚事务 */
     rollbackTransaction(): Promise<void>;
+    /** 创建 Savepoint */
+    savepoint?(name: string): Promise<void>;
+    /** 回滚到 Savepoint */
+    rollbackToSavepoint?(name: string): Promise<void>;
+    /** 释放 Savepoint */
+    releaseSavepoint?(name: string): Promise<void>;
+    /** 在线备份：导出全库一致性快照 */
+    backup?(): Promise<Record<string, Record<string, unknown>[]>>;
 }
 
 /**
@@ -237,6 +245,11 @@ interface DropTableStatement {
     /** IF EXISTS — 表不存在时不报错 */
     ifExists?: boolean;
 }
+/** EXPLAIN 查询计划 */
+interface ExplainStatement {
+    type: 'EXPLAIN';
+    query: Statement;
+}
 interface InsertStatement {
     type: 'INSERT';
     into: string;
@@ -272,7 +285,7 @@ interface SelectStatement {
     limit?: number;
     offset?: number;
 }
-type Statement = SelectStatement | InsertStatement | UpdateStatement | DeleteStatement | CreateTableStatement | DropTableStatement;
+type Statement = SelectStatement | ExplainStatement | InsertStatement | UpdateStatement | DeleteStatement | CreateTableStatement | DropTableStatement;
 
 /**
  * metona-sqlark Query Executor — AST 执行器
@@ -285,6 +298,8 @@ declare class QueryExecutor {
     private engine;
     constructor(engine: IStorageEngine);
     execute(stmt: Statement): Promise<unknown>;
+    /** EXPLAIN: 输出查询计划 */
+    private executeExplain;
     private executeSelect;
     private executeJoinSelect;
     private prefixRow;
@@ -697,6 +712,11 @@ declare class AriaEngine implements IStorageEngine {
     beginTransaction(): Promise<void>;
     commitTransaction(): Promise<void>;
     rollbackTransaction(): Promise<void>;
+    private savepoints;
+    savepoint(name: string): Promise<void>;
+    rollbackToSavepoint(name: string): Promise<void>;
+    releaseSavepoint(name: string): Promise<void>;
+    backup(): Promise<Record<string, Record<string, unknown>[]>>;
     private getAllRows;
     private getPK;
     private validateRow;
@@ -713,6 +733,13 @@ declare class AriaEngine implements IStorageEngine {
     private indexScanToRows;
     /** 每 10 次 gc 计数器触发一次 MVCC 垃圾回收 */
     private tryGC;
+    /** 检查内存预算，超出时强制 flush + GC */
+    private checkMemoryBudget;
+    /**
+     * ANALYZE: 收集表统计信息
+     * 返回行数、平均行大小、索引深度等
+     */
+    analyzeTable(tableName: string): Promise<Record<string, unknown>>;
     private ensureOpen;
     private ensureTable;
     /** Get the number of WAL records stored */