Add nuget MCP to `.vscode/mcp.json`

see https://www.nuget.org/packages/NuGet.Mcp.Server/

this would allow the creation of a workflow that would periodically upgrade libraries (for cases where dependabot won't be smart enough to make required code-changes).

adding the following to `.vscode/mcp.json`
```json
{
"servers": {
"NuGet.Mcp.Server": {
"type": "stdio",
"command": "dnx",
"args": ["NuGet.Mcp.Server@1.1.24", "--yes"]
}
}
}
```

Open .vscode/mcp.json and compare its existing server entries with the NuGet.Mcp.Server package information linked in the issue. Add the requested server configuration, then verify that the JSON remains valid and that the NuGet MCP server can be invoked through the configured dnx command.

Written by the indexing model from the issue text.