SSE transport for server does not work inside custom Ktor's Route #94 (#236 and #237)

[IainHull]

This should also fix Issues #236 and #237

Changes the Ktor API from

fun Routing.mcp(block: ServerSSESession.() -> Server)

to

fun Route.mcp(block: suspend ServerSSESession.() -> Server)

Motivation and Context

This fixes

• mcp inside a route is bound to the path specified in the route not the root path.
• ability to publish multiple mcp servers
• can create the server asynchronously
• together this enables developers to created multi tenanted mcp servers

This enables code the following style of code

routing {
    route("mcp/{application}") {
        mcp {
            val authHeader = call.request.header("Authorization") ?: throw IllegalArgumentException("Authorization header required")
            val application = call.parameters["application"] ?: throw IllegalArgumentException("Application required")
            return@mcpFixed mcpServerManager.getOrCreateServer(authHeader, application)
        }
    }
}

How Has This Been Tested?

Tested this with npx @modelcontextprotocol/inspector and Flowise

Breaking Changes

This maintains source compatibility, but not binary compatibility.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

Address

• #237 - Route.mcp() needed to register routes correctly with Ktor
• #236 - Passing info about user/tenant to tools
• #94 - SSE transport for server does not work inside custom Ktor's Route

[IainHull]

Sorry for the churn, there were two pieces missing from my initial commit.

@kpavlov would you be able to trigger another build?

[kpavlov]

Incorporated in #531