Add markdown support to project description

Markdown renders just fine in the project descriptions on Github's projects page, though not in this plugin.
Since I'm using links in the project description to link to other places for referencing purposes, it would be nice if these links and text formatting would work.
Optionally, you could make this a toggle so it can be enabled if required, to avoid potential performance issues.

The issue names no files or tests. Start by locating the VS Code project-description rendering entry point and inspect how descriptions are displayed; confirm whether links and text formatting render, and clarify whether an opt-in toggle is required. Done means Markdown formatting and links work in project descriptions, with any agreed toggle covered.