Remove client-side changes outside the scope of issue #295

The issue only reports encoding inconsistency in
StdioServerTransportProvider. Revert StdioClientTransport to its
original state to keep the PR scoped to the reported problem.

Author: xxxxxxjun

mcp-core/src/main/java/io/modelcontextprotocol/client/transport/StdioClientTransport.java

@@ -180,7 +180,7 @@ public void awaitForExit() {
 	private void startErrorProcessing() {
 		this.errorScheduler.schedule(() -> {
 			try (BufferedReader processErrorReader = new BufferedReader(
-					new InputStreamReader(process.getErrorStream(), StandardCharsets.UTF_8))) {
+					new InputStreamReader(process.getErrorStream()))) {
 				String line;
 				while (!isClosing && (line = processErrorReader.readLine()) != null) {
 					try {
@@ -246,8 +246,7 @@ public Mono<Void> sendMessage(JSONRPCMessage message) {
 	 */
 	private void startInboundProcessing() {
 		this.inboundScheduler.schedule(() -> {
-			try (BufferedReader processReader = new BufferedReader(
-					new InputStreamReader(process.getInputStream(), StandardCharsets.UTF_8))) {
+			try (BufferedReader processReader = new BufferedReader(new InputStreamReader(process.getInputStream()))) {
 				String line;
 				while (!isClosing && (line = processReader.readLine()) != null) {
 					try {