Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

Backport of #800 to the 0.18.x line.

Instead of returning Mono.error with an McpError, DefaultMcpStatelessServerHandler
now returns a JSON-RPC method not found error (-32601), aligned with the stateful
server session handler.

The early return meant the error never reached the onErrorResume below it, so it
escaped to the transport. HttpServletStatelessServerTransport and the Spring
WebMvc/WebFlux stateless transports all map an escaping handler error to HTTP 500,
so any request for a method with no registered handler was answered with a server
error rather than a JSON-RPC error response. Clients probing for optional methods
-- OpenAI's hosted connector sends server/discover before tools/list -- therefore
drove 5xx traffic against otherwise healthy servers.

Adds the unit test from #800 and an integration test that asserts both the HTTP
status and the JSON-RPC error body, since the status is what regressed.

See #1085

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

)

Backport #1182

(cherry picked from commit 7aa05da)

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

Backport of #1130.

Also includes the changes from 4186ca1 (resumed streams are registered
as the listening stream) and ff78191 (close the response stream after
sending a method-not-found error), which #1130 builds upon.

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

Port of spring-projects/spring-ai@023867c
to the WebFlux and WebMvc Streamable HTTP server transports.

Give users the ability to configure maxSessions and a mechanism to evict
idle sessions. Initialize requests carrying an Mcp-Session-Id header are
rejected, and sessions removed through DELETE are no longer tracked.

Signed-off-by: Dimitar Proynov <dimitar.proynov@broadcom.com>
Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

See b43bf03

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>