[Feature]: 控制台提醒

## Summary

[One or two sentences: what do you want and why?]
Copaw现在有/approve，以后可能其他需要授权的环节，所以，希望给控制台添加浏览器提醒，就像qwen code CLI需要授权或完成任务后给用户的提醒。

## Component(s) Affected

- [ ] Core / Backend (app, agents, config, providers, utils, local_models)
- [x] Console (frontend web UI)
- [ ] Channels (DingTalk, Feishu, QQ, Discord, iMessage, etc.)
- [ ] Skills
- [ ] CLI
- [ ] Documentation (website)
- [ ] Tests
- [ ] CI/CD
- [ ] Scripts / Deploy

## Problem / Motivation

[What problem does this solve? Who benefits?]

## Proposed Solution

[Describe the feature or change you have in mind. Be as specific as possible.]

## Alternatives Considered

[Any other approaches or workarounds you thought about.]

## Additional Context

[Screenshots, examples, links to docs or similar features elsewhere.]

## Willing to Contribute

- [ ] I am willing to open a PR for this feature (after discussion).