Fix SSH relay/socket regressions and restore session/focus contracts

daemon/remote/cmd/cmuxd-remote/cli.go

@@ -5,7 +5,9 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"io"
 	"net"
 	"os"
 	"path/filepath"
@@ -433,12 +435,42 @@ func socketRoundTrip(socketPath, command string, refreshAddr func() string) (str
 		return "", fmt.Errorf("failed to send command: %w", err)
 	}
 
+	// V1 handlers may return multiple lines (e.g. list_windows). Read until
+	// the stream goes idle briefly after seeing at least one newline.
 	reader := bufio.NewReader(conn)
-	line, err := reader.ReadString('\n')
-	if err != nil {
-		return "", fmt.Errorf("failed to read response: %w", err)
+	var response strings.Builder
+	sawNewline := false
+
+	for {
+		readTimeout := 15 * time.Second
+		if sawNewline {
+			readTimeout = 120 * time.Millisecond
+		}
+		_ = conn.SetReadDeadline(time.Now().Add(readTimeout))
+
+		chunk, err := reader.ReadString('\n')
+		if chunk != "" {
+			response.WriteString(chunk)
+			if strings.Contains(chunk, "\n") {
+				sawNewline = true
+			}
+		}
+
+		if err != nil {
+			if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
+				if sawNewline {
+					break
+				}
+				return "", fmt.Errorf("failed to read response: timeout waiting for response")
+			}
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			return "", fmt.Errorf("failed to read response: %w", err)
+		}
 	}
-	return strings.TrimRight(line, "\n"), nil
+
+	return strings.TrimRight(response.String(), "\n"), nil
 }
 
 // socketRoundTripV2 sends a JSON-RPC request and returns the result JSON.