Add a link to mermaid.live render for mermaid markdown

[mitchellgordon95]

When you ask the model to generate a diagram:

It will generate a link you can CMD-Click in iTerm to view it in the browser:

[CLAassistant]

All committers have signed the CLA.

[paul-gauthier]

Thanks for your interest in aider and for making this PR. This is an interesting idea, but probably out of scope to merge.

[mitchellgordon95]

I understand if you'd like to keep the codebase tight and focused.

But if you're open to being convinced, here are a few examples of useful graphs that I have generated to grok the architecture of some projects.

"show me how the chess game state is managed"

"show me how the API is making calls to Claude to generate chess moves"

(aider repo) "make a UML graph that shows the major components of this project and how they interact"

IMO people would have a better UX if they learned to ask for graphs more often.