test: usar setDb y resetDb para configurar y limpiar BD en tests

Co-authored-by: aider (openrouter/openai/gpt-5) <aider@aider.chat>

tests/unit/tasks/service.list-active.test.ts

@@ -1,6 +1,7 @@
 import Database from 'bun:sqlite';
 import { initializeDatabase, ensureUserExists } from '../../../src/db';
 import { TaskService } from '../../../src/tasks/service';
+import { setDb, resetDb } from '../../../src/db/locator';
 
 describe('TaskService - listAllActive', () => {
   let memdb: Database;
@@ -10,11 +11,11 @@ describe('TaskService - listAllActive', () => {
     process.env.GROUP_GATING_MODE = 'off';
     memdb = new Database(':memory:');
     initializeDatabase(memdb);
-    (TaskService as any).dbInstance = memdb;
+    setDb(memdb);
   });
 
   afterEach(() => {
-    try { memdb.close(); } catch {}
+    try { resetDb(); memdb.close(); } catch {}
   });
 
   function seedGroup(id: string, name: string = 'Group') {