Update MCP template readme to switch to VS IDE context

[joelverhagen]

Description

Right now the README is worded for VS Code. But the template works in VS IDE. And VS IDE has MCP support too.

The README could be reworded and have a VS IDE version appear when the VS IDE template is used.

Template:
https://github.com/dotnet/extensions/blob/main/src/ProjectTemplates/Microsoft.Extensions.AI.Templates/src/McpServer/McpServer-CSharp/README.md

Maybe we do
(hostIdentifier != \"dotnetcli\") on a README.VisualStudio.md in the template.json, like we have for opening the README:

extensions/src/ProjectTemplates/Microsoft.Extensions.AI.Templates/src/McpServer/McpServer-CSharp/.template.config/template.json

Line 36 in 294a33d

"condition": "(hostIdentifier != \"dotnetcli\" && hostIdentifier != \"dotnetcli-preview\")",

Reproduction Steps

Install the AI template package.
Create a project using the MCP server template in VS IDE.

Expected behavior

It should have VS IDE instructions.

Actual behavior

Notice the README mentions VS Code.

Regression?

No

Known Workarounds

No response

Configuration

No response

Other information

No response