refactor: remove deprecated 0.7.0 code

These changes are part of the planned deprecation cycle announced in 0.8.0,
with the deprecated classes scheduled for removal in 0.9.0

- Delete WebFluxSseServerTransport, WebMvcSseServerTransport, StdioServerTransport, and HttpServletSseServerTransport
- Remove deprecated interfaces: ServerMcpTransport, ClientMcpTransport
- Delete DefaultMcpSession implementation
- Remove all deprecated test classes for the removed implementations
- Update references to use McpServerTransport and McpClientTransport interfaces

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

Author: tzolov

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

@@ -8,18 +8,16 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import io.modelcontextprotocol.spec.McpError;
 import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.McpServerSession;
 import io.modelcontextprotocol.spec.McpServerTransport;
 import io.modelcontextprotocol.spec.McpServerTransportProvider;
-import io.modelcontextprotocol.spec.McpServerSession;
-import io.modelcontextprotocol.spec.ServerMcpTransport;
 import io.modelcontextprotocol.util.Assert;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import reactor.core.Exceptions;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.FluxSink;
 import reactor.core.publisher.Mono;
-import reactor.core.publisher.Sinks;
 
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;