#21636: feat/tasks tab

- **feat(gateway-ui): add Tasks tab** - **fix(gateway): route tasks API under control-ui basePath** <!-- greptile_comment --> <h3>Greptile Summary</h3> Added a Tasks tab to the gateway control UI with full CRUD API support for task management. The backend properly routes `/api/tasks` under the `controlUiBasePath`, but the frontend fetch calls use hardcoded paths without considering `basePath`, which will break when the gateway is configured with a non-root `controlUiBasePath` (e.g., `/openclaw`). <h3>Confidence Score: 3/5</h3> - Safe to merge with one critical path issue - The implementation is well-structured with proper auth, validation, and sanitization. However, the frontend API calls don't respect `basePath`, which will cause failures in non-root deployments. This is a critical bug for users with custom base paths configured. - Pay close attention to `ui/src/ui/views/tasks.ts` - all fetch calls need basePath support _{Last reviewed commit: 48fb33c} <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} <!-- /greptile_comment -->