Access WSL tunnels from Agents web UI

> I'm writing this comment because I see that this issue was renamed from **AgentHost: WSL and Dev Containers support** to **AgentHost: Dev Containers support**, and I'm not sure if I'm experiencing something unique or something that is already being tracked in another issue. My situation is specific to WSL, so that's why I'm confused.
>
> I tried to demonstrate the issue in the video below. Basically, I can't access my WSL remote tunnel WSL filesystem from https://vscode.dev/agents or https://insiders.vscode.dev/agents; I can only access it from https://vscode.dev/, where I have the WSL extension installed. The agents window remote tunnel connection only exposes my Windows filesystem; it does not expose my WSL filesystem.
>
> https://github.com/user-attachments/assets/d12a1ee2-0621-4852-9533-c28f4cde132e

_Originally posted by @Knufle in [#317380](https://github.com/microsoft/vscode/issues/317380#issuecomment-5655932557)_