Toasts require the surreal JS library

**Issue Type**
- [ x] Existing documentation (e.g. typos, errors, outdated information)
- [ ] Suggest new documentation that is currently missing

**Current Behavior or Documentation Gaps**
When using toasts the surreal package MUST be included otherwise toasts won't work.
This is not documented and using `app = FastHTML(surreal=False,...)` toasts failed to show.
Please include this dependency in the description of the toast functionality.

**Relevant Links**
[Toast documentation](https://docs.fastht.ml/tutorials/quickstart_for_web_devs.html#toasts-also-known-as-messages)

**Confirmation**
Please confirm the following:
- [x ] I have checked the existing issues and pull requests to ensure this documentation issue hasn't been reported before.
- [x] I have read the project's documentation and am confident this issue or suggestion is valid.