Feat: Enhance Neural Buffer UX

There are some additional features we can add that would make the neural buffer easier to use such as:
- Show the currently active model for the buffer
- Change the active model just for the buffer
- Change settings for the model just for the buffer
- Surface various details about the Neural buffer:
- Live token counter for the current model e.g. 100/4096 through virtual text or floating window
- Show current temperature, Top P, Frequency Penalty, Presence penalty, etc.
- Add markdown syntax highlighting for buffer