use with craftos-pc indexes PC root dir

還沒有人認領這個 Issue。

### How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

### Which OS are you using?

Windows

### What is the issue affecting?

Other

### Expected Behaviour

not index every file on PC by recursively going through root dir

### Actual Behaviour

accepts / as valid workspace directory, causing every file on my PC to be indexed

the fix done for #2159 seems to be incorrect - it should not index every file on my PC if I have a CraftOS workspace open. if it can't support the virtual filesystem, it should just ignore it. instead the extension is completely unusable in this configuration when trying to use craftos remote, even with attempting to override the force-accept-workspace parameter to false on user-level in vscode preferences. (maybe this is ignored for some reason? it's defaulted to true so would make sense)
not sure if this is an issue to be made on the vscode-lua extension or the LSP itself!

### Reproduction steps

1. Use CraftOS-PC in a project, and connect to a remote computer in Minecraft
2. With the vscode-lua extension enabled, watch as every Lua file on PC is indexed because the root dir for the VFS is technically /

### Additional Notes

_No response_

### Log File

_No response_

按照列出的步驟，在啟用 sumneko.lua Visual Studio Code 擴充功能的情況下重現 CraftOS-PC 遠端工作區案例。首先追蹤虛擬檔案系統根目錄 `/` 和 `force-accept-workspace` 設定的處理方式，然後驗證開啟此工作區時不再遞迴索引主機 PC。

由索引模型根據 Issue 內容生成。