Cannot install .NET SDK 9.0.313

### Describe the bug.

When I am trying building [Windows Package Manager Manifest Creator 1.12.13.0](https://github.com/microsoft/winget-create/releases/tag/v1.12.13.0) in VS Code, this extension posts

```text
Installing .NET SDK 9.0.313: Preparing...
```

to a notification bar, which keeps rolling.

### Please attach log file(s) here if you have any.

It looks like you may be offline (can you connect to www.microsoft.com?) and have no compatible installations of .NET 9.0.313 for ms-dotnettools.vscode-dotnet-runtime.
Installation will timeout in 600 seconds.

Error : (DotnetOfflineFailure)

### Reproduction Steps

1. Clone [Windows Package Manager Manifest Creator 1.12.13.0](https://github.com/microsoft/winget-create/releases/tag/v1.12.13.0)
2. Build it

### Expected Behavior

N/A

### Exceptions & Errors (if any)

_No response_

### .NET Install Tool Version

3.1.0

### Your operating system? Please provide more detail, such as the version and or distro above.

Windows

### VS Code Version

版本: 1.134.0 (user setup) 提交: 110a328ea54b42367b803ec53ee0bf52ef26b419 日期: 2026-08-18T18:24:44Z Electron: 42.8.1 ElectronBuildId: 14906494 Chromium: 148.0.7778.280 Node.js: 24.18.1 V8: 14.8.178.38-electron.0 OS: 1.0.81-0

Start by reproducing the failure while building Windows Package Manager Manifest Creator 1.12.13.0 in VS Code on Windows, using .NET Install Tool 3.1.0 and the reported SDK version. Check the extension's installation path and the supplied DotnetOfflineFailure details; done means the cause is verified and the issue has a confirmed fix or actionable diagnosis.

Written by the indexing model from the issue text.