Allow 'npipe://' prefix in Docker host address

Update `LocalHttpClientTransport` to support explicit `npipe://` prefix
in the host name. This is the format used in the Docker config from
v4.31.1 onward.

Fixes gh-41199

Author: philwebb

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/transport/LocalHttpClientTransport.java

@@ -116,6 +116,8 @@ public String resolveCanonicalHostname(String host) throws UnknownHostException
 	 */
 	private static class LocalConnectionSocketFactory implements ConnectionSocketFactory {
 
+		private static final String NPIPE_PREFIX = "npipe://";
+
 		private final String host;
 
 		LocalConnectionSocketFactory(String host) {
@@ -124,10 +126,10 @@ private static class LocalConnectionSocketFactory implements ConnectionSocketFac
 
 		@Override
 		public Socket createSocket(HttpContext context) throws IOException {
-			if (Platform.isWindows()) {
-				return NamedPipeSocket.get(this.host);
+			if (this.host.startsWith(NPIPE_PREFIX)) {
+				return NamedPipeSocket.get(this.host.substring(NPIPE_PREFIX.length()));
 			}
-			return DomainSocket.get(this.host);
+			return (!Platform.isWindows()) ? DomainSocket.get(this.host) : NamedPipeSocket.get(this.host);
 		}
 
 		@Override