fix(mcp): remove GET redirect that blocks Streamable HTTP SSE stream (#2728)

The MapGet("/") redirect on the MCP group root caused an infinite 301
redirect loop for GET requests to /docs/_mcp/. The Streamable HTTP
transport uses GET on the same endpoint as POST to open the SSE stream
for server-to-client notifications. The redirect intercepted every GET
before it could reach the MCP handler, causing Cursor to enter a
"fetch failed" reconnect loop and never finish loading tools.

Co-authored-by: Claude <claude@anthropic.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

Author: 3 people

src/api/Elastic.Documentation.Mcp.Remote/Program.cs

@@ -97,7 +97,6 @@
 	_ = mcp.MapHealthChecks("/health");
 	_ = mcp.MapHealthChecks("/alive", new HealthCheckOptions { Predicate = r => r.Tags.Contains("live") });
 	_ = mcp.MapMcp("");
-	_ = mcp.MapGet("/", () => Results.Redirect(mcpPrefix, permanent: true));
 
 	Console.WriteLine("MCP server startup completed successfully");
 	app.Run();