Further enhance Live Share support

[ElianHugh]

Live Share currently extends session watcher capabilities to guest sessions. However, there are some features that are currently lacking. This issue serves as a checklist for improving Live Share.

General Improvements

• [ ] Share all active servers that were started prior to Live Share session
• [ ] Open shared servers in webview via tree view items

R Markdown is currently missing the following for guests:

• [ ] Run chunk commands
• [ ] Preview rmd files

CodeSpaces

• [ ] Codespace support is potentially lacking? Can't check without access

[github-actions[bot]]

This issue is stale because it has been open for 365 days with no activity.

[ElianHugh]

unstale