fix: configurar DB global en tests con setDb y eliminar dbInstance

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

tests/unit/services/command.date-parsing.test.ts

@@ -3,6 +3,7 @@ import { Database } from 'bun:sqlite';
 import { initializeDatabase } from '../../../src/db';
 import { TaskService } from '../../../src/tasks/service';
 import { CommandService } from '../../../src/services/command';
+import { setDb } from '../../../src/db/locator';
 
 import { ymdInTZ, addDaysToYMD } from '../../helpers/dates';
 
@@ -13,8 +14,7 @@ describe('CommandService - parser de fechas (hoy/mañana y formatos YYYY/YY-MM-D
   beforeAll(() => {
     memdb = new Database(':memory:');
     initializeDatabase(memdb);
-    TaskService.dbInstance = memdb;
+    setDb(memdb);
-    CommandService.dbInstance = memdb;
   });
 
   beforeEach(() => {