fix(ipc): drop non-blocking accept busy-poll in listener loop

The IPC server set the listener to non-blocking and slept 100 ms between
WouldBlock errors. There is no shutdown signal feeding the loop, so the
non-blocking pattern only added up to ~100 ms of latency before each
accepted connection plus continuous busy-poll wakeups.

Switching to blocking accept removes the latency and the wakeups, and
restores deterministic ordering for the in-tree IPC integration tests
that previously flaked under cargo test parallelism (the listener could
be mid-sleep when a connection arrived, pushing command delivery past
the test's 2 s polling window).

Author: irudoy

src/ipc/server.rs

@@ -32,11 +32,6 @@ impl IpcServer {
         let listener = TcpListener::bind(format!("127.0.0.1:{}", port))
             .map_err(|e| format!("Failed to bind to port {}: {}", port, e))?;
 
-        // Set non-blocking so we can check for shutdown
-        listener
-            .set_nonblocking(true)
-            .map_err(|e| format!("Failed to set non-blocking: {}", e))?;
-
         let (command_tx, command_rx) = mpsc::channel();
 
         // Spawn the listener thread
@@ -79,10 +74,6 @@ impl IpcServer {
                         Self::handle_connection(stream, tx);
                     });
                 }
-                Err(ref e) if e.kind() == std::io::ErrorKind::WouldBlock => {
-                    // No connection available, sleep briefly
-                    thread::sleep(std::time::Duration::from_millis(100));
-                }
                 Err(e) => {
                     tracing::error!("Error accepting connection: {}", e);
                     thread::sleep(std::time::Duration::from_millis(100));