refactor: change notification params type from Map<String,Object> to Object (#137)

* refactor: change notification params type from Map<String,Object> to Object

This change generalizes the parameter type for notification methods across the MCP framework,
allowing for more flexible parameter passing. Instead of requiring parameters to be structured
as a Map<String,Object>, the API now accepts any Object as parameters.

The primary motivation is to simplify client usage by allowing direct passing of strongly-typed
 objects without requiring conversion to a Map first, as demonstrated in the McpAsyncServer
logging notification implementation.

Affected components:

- McpSession interface and implementations
- McpServerTransportProvider interface and implementations
- McpSchema JSONRPCNotification record
---------

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

mcp/src/test/java/io/modelcontextprotocol/MockMcpServerTransportProvider.java

@@ -47,7 +47,7 @@ public class MockMcpServerTransportProvider implements McpServerTransportProvide
 	}
 
 	@Override
-	public Mono<Void> notifyClients(String method, Map<String, Object> params) {
+	public Mono<Void> notifyClients(String method, Object params) {
 		return session.sendNotification(method, params);
 	}