docs: 补充 v1.2.7 登录验证（滑块 / Turnstile / Cap）文档

docs-site/en/guide/local-dev.md

@@ -28,6 +28,7 @@ Open `http://localhost:3000/setup` to create the admin account. Data directory d
 | `npm run typecheck` | Type check |
 | `npm test` | Unit tests |
 | `npm run reset-password` | Reset password (optional username) |
+| `npm run slider` | Reset login verification to local slider |
 | `npm run migrate` | Preview legacy dir migration (`-- --apply` to run) |
 
 ## Dev-only variables