[DOCS] MonsterUI concise guide section needs to be improved

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- [x] Existing documentation (e.g. typos, errors, outdated information)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

**Current Behavior or Documentation Gaps**

The concise guide section on MonsterUI does not include the core information about using MonsterUI, and the API list is missing enum members which is critical for LLMs and they hallucinate otherwise. Key areas include:
- Layout Helpers
- Typography (markdown and semantic)
- Forms
- Enum styling usage

**Suggested Improvement or New Documentation Content**
See PR

**Relevant Links**

https://github.com/AnswerDotAI/fasthtml/blob/main/nbs/ref/concise_guide.ipynb

**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.