Add stdio transport support to EverythingServer sample

[Copilot]

Addresses modelcontextprotocol#889. PR modelcontextprotocol#709 converted EverythingServer to HTTP-only; this restores stdio support while maintaining HTTP.

Architecture

Split EverythingServer into three projects following the approach suggested in modelcontextprotocol#709 review:

• EverythingServer.Core - Shared library with all MCP handlers (tools, prompts, resources, subscription management). Exposes AddEverythingMcpHandlers() extension method.
• EverythingServer.Http - HTTP transport using ASP.NET Core. Per-session subscriptions managed via RunSessionHandler.
• EverythingServer.Stdio - Stdio transport using Microsoft.Extensions.Hosting. Single-session with global subscriptions, background services as hosted services, stderr logging.

Usage

Both implementations share identical MCP functionality:

// HTTP (EverythingServer.Http/Program.cs)
var builder = WebApplication.CreateBuilder(args);
builder.Services
    .AddMcpServer()
    .WithHttpTransport(options => { /* session handler */ })
    .AddEverythingMcpHandlers(subscriptions);

// Stdio (EverythingServer.Stdio/Program.cs)
var builder = Host.CreateApplicationBuilder(args);
builder.Services
    .AddMcpServer()
    .WithStdioServerTransport()
    .AddEverythingMcpHandlers(subscriptions);

Files Changed

• Created samples/EverythingServer.Core/ with shared handlers
• Created samples/EverythingServer.Stdio/ for stdio implementation
• Renamed samples/EverythingServer/ → samples/EverythingServer.Http/
• Updated ModelContextProtocol.slnx with new projects
• Added README files documenting each project

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• aka.ms
  • Triggering command: curl -I -sSL --retry 5 --retry-delay 2 --connect-timeout 15 REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

can you create a PR to address modelcontextprotocol#889 ? the PR modelcontextprotocol#709 moved the EverythingServer sample from being stdio to http, but we need the option to run stdio too.

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