Serve sse and streamable from a single port

[ardaguclu]

Fixes #135
Fixes #117

This is a continuation effort based on this comment #128 (comment).

This PR serves a unified http mux to support sse and streamable http in the same url (with their own specific endpoints). This paves the way for us to provide a singular middlewares such as authorization, audit logs, etc.

Consequently this PR introduces new flag port that will be used for both mcp transport types. This PR deprecates sse-port and http-port in favor of new port flag (we still keep backwards compatibility by only deprecating flags for now).

In the next iterations;

• we'll need to introduce middlewares to reject requests with appropriate http statuses as suggested in MCP Protocol design (shown in feat(config): deny resources by using RESTMapper as an interceptor #149 (comment))
• we'll need to catch the kill signals and gracefully shutdown the http server.

[ardaguclu]

@manusa wondering your opinions about this PR?. Thanks.

[manusa]

@manusa wondering your opinions about this PR?. Thanks.

❤️ This is exactly what I had in mind

I haven't checked it thoroughly, but I think that the mux impl belongs elsewhere (probably in the mcp package.

[ardaguclu]

I haven't checked it thoroughly, but I think that the mux impl belongs elsewhere (probably in the mcp package.

We'll have to catch sig terms and exit the entire application

[ardaguclu]

This PR fixes #135

[ardaguclu]

This PR fixes #117 as well

[manusa]

LGTM, thx!