fix(acp): Fix stdin/stdout mapping in TypeScript ACP agent server

- Corrected ndJsonStream parameter order (output before input)
- Added comprehensive test scripts for ACP protocol testing
- Verified initialize, session/new, and session/prompt work correctly
- JS CLI can now successfully act as ACP agent server

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: phodal

mpp-ui/src/jsMain/typescript/agents/acp/AcpAgentServer.ts

@@ -332,10 +332,12 @@ class AcpSessionRenderer {
 export async function startAcpAgentServer(): Promise<void> {
   console.error('[ACP Agent] Starting AutoDev Xiuper ACP Agent Server...');
 
-  const input = Writable.toWeb(process.stdout) as WritableStream;
-  const output = Readable.toWeb(process.stdin) as ReadableStream;
+  // For ACP ndJsonStream: first param is output (where we write), second is input (where we read)
+  // We write JSON responses to stdout, read JSON requests from stdin
+  const output = Writable.toWeb(process.stdout) as WritableStream<Uint8Array>;
+  const input = Readable.toWeb(process.stdin) as ReadableStream<Uint8Array>;
 
-  const stream = acp.ndJsonStream(input, output);
+  const stream = acp.ndJsonStream(output, input);
 
   const connection = new acp.AgentSideConnection(
     (conn) => new AutoDevAcpAgent(conn),