fix: 消除并发测试中的 tool 导出竞争和 SQLite 目录碰撞

tests/helpers.ts

@@ -1,4 +1,5 @@
 import Database from "bun:sqlite";
+import { randomUUID } from "node:crypto";
 import { mkdirSync, rmSync } from "node:fs";
 import { rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
@@ -105,7 +106,7 @@ export function createTestDatabase(prefix: string, migrations: MigrationRecord[]
 }
 
 export function makeTempDir(prefix: string): string {
-  const dir = join(tmpdir(), `${prefix}-${Date.now()}-${Math.random().toString(36).slice(2)}`);
+  const dir = join(tmpdir(), `${prefix}-${randomUUID()}`);
   mkdirSync(dir, { recursive: true });
   return dir;
 }