[Feature]: mermaid render support within the markdown render view

[tnh]

Before submitting

• I searched existing issues and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

apps/desktop

Problem or use case

Like other editors, I would like t3code to render mermaid diagrams encoded in markdown.

Proposed solution

Example mermiad diagram rendered within Cursor

Why this matters

GitHub supports mermiad https://docs.github.com/en/get-started/writing-on-github/working-with-advanced-formatting/creating-diagrams

Most other providers support mermiad diagramts.

Smallest useful scope

Have t3code use https://github.com/mermaid-js/mermaid

Alternatives considered

No response

Risks or tradeoffs

No response

Examples or references

No response

Contribution

• I would be open to helping implement this.