fix: manejar error EEXIST al crear directorio data

src/db.ts

@@ -5,8 +5,12 @@ import { join } from 'path';
 
 // Function to get a database instance. Defaults to 'data/tasks.db'
 export function getDb(filename: string = 'tasks.db'): Database {
-  // Create data directory if it doesn't exist
+  // Try to create data directory if it doesn't exist (ignore if already exists)
+  try {
     mkdirSync('data', { recursive: true });
+  } catch (err) {
+    if (err.code !== 'EEXIST') throw err; // Only ignore "already exists" errors
+  }
   return new Database(join('data', filename));
 }