feat: HttpServlet Streamable HTTP server implementation (#290)

Implementation of the Streamable HTTP transport provider for the Servlet API.

---
Signed-off-by: Christian Tzolov <[email protected]>
Co-authored-by: Christian Tzolov <[email protected]>
Co-authored-by: Zachary German <[email protected]>

Author: 3 people

mcp-spring/mcp-spring-webflux/src/main/java/io/modelcontextprotocol/server/transport/WebFluxStreamableServerTransportProvider.java

@@ -440,4 +440,4 @@ public WebFluxStreamableServerTransportProvider build() {
 
 	}
 
-}
+}