fix: update gitignore paths from canto-backend/frontend to backend/frontend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -26,16 +26,16 @@ checkpoints/
 docker/models/
 docker/data/
 docker/.env
-canto-frontend/node_modules/
-canto-frontend/dist/
-canto-frontend/.env
-canto-frontend/.env.local
+frontend/node_modules/
+frontend/dist/
+frontend/.env
+frontend/.env.local
 CLAUDE.md
 样本.mp3
 aliyun.md
 /nginx.conf
 deploy.md
-canto-backend/scripts
-canto-backend/examples
-canto-backend/canto.service
-canto-frontend/.env.production
+backend/scripts
+backend/examples
+backend/canto.service
+frontend/.env.production