Add goTool clients subcommand for CLIENT_INFO query.

Refactor into version/clients subcommands with shared serial framing
to list registered slaves from the master over UART.

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

goTool/cmd_version.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+
+	"google.golang.org/protobuf/proto"
+
+	"powerpod/gotool/pb"
+)
+
+func runVersion(sp *serialPort) error {
+	payload, err := sp.exchange(byte(pb.MessageType_VERSION), "VERSION")
+	if err != nil {
+		return err
+	}
+
+	var msg pb.UartMessage
+	if err := proto.Unmarshal(payload[1:], &msg); err != nil {
+		return fmt.Errorf("decode protobuf: %w", err)
+	}
+
+	if msg.GetType() != pb.MessageType_VERSION {
+		return fmt.Errorf("unexpected message type %v", msg.GetType())
+	}
+
+	ver := msg.GetVersionResponse()
+	if ver == nil {
+		return fmt.Errorf("response missing version_response")
+	}
+
+	fmt.Printf("version:  %d\n", ver.GetVersion())
+	fmt.Printf("git_hash: %s\n", ver.GetGitHash())
+	return nil
+}