fix: filter template resources from standard resource listing (#528)

- Add filter to exclude resources with template parameters ({}) from resources/list
- Template resources should only appear in resources/templates/list per MCP spec
- Add comprehensive test coverage for resource/template separation
- Update mock transport utilities for better test support

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

mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java

@@ -594,6 +594,7 @@ public class McpAsyncServer {
 			var resourceList = this.resources.values()
 				.stream()
 				.map(McpServerFeatures.AsyncResourceSpecification::resource)
+				.filter(resource -> !resource.uri().contains("{"))
 				.toList();
 			return Mono.just(new McpSchema.ListResourcesResult(resourceList, null));
 		};
@@ -906,4 +907,4 @@ public class McpAsyncServer {
 		this.protocolVersions = protocolVersions;
 	}
 
-}
+}