Add optional Windows Explorer context menu for file-based apps

### Is your feature request related to a problem?

No specific problem.

This is an enhancement request to improve the Windows experience for .NET file-based apps and make the feature easier to discover.

### Describe the solution you'd like

.NET 10 File-based Apps are great for scripts and small utilities.

On Windows, it would be convenient if installing the .NET SDK could optionally register a context menu such as:

Run with .NET

Publish with .NET

This would avoid changing the default .cs file association (which many users expect to open in an editor), while still making file-based apps much easier to discover and use from Windows Explorer.

The context menu could be installed as an optional SDK feature.

### Alternatives you've considered

Currently, the only option is to open a terminal and run:

dotnet app.cs

Users can also manually create a custom launcher or modify file associations, but these require additional setup and are not discoverable for most users.

### Additional context

_No response_