add basic client TCPConnector to directly connect to a gRPC endpoint

internal/cli/client/connector/tcp.go

@@ -0,0 +1,33 @@
+package connector
+
+import (
+	"context"
+	"fmt"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"net/netip"
+)
+
+// TCPConnector establishes a connection to the machine API through a direct TCP connection to an API endpoint.
+type TCPConnector struct {
+	apiAddr netip.AddrPort
+}
+
+func NewTCPConnector(apiAddr netip.AddrPort) *TCPConnector {
+	return &TCPConnector{apiAddr: apiAddr}
+}
+
+func (c *TCPConnector) Connect(_ context.Context) (*grpc.ClientConn, error) {
+	conn, err := grpc.NewClient(
+		c.apiAddr.String(),
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("create machine API client: %w", err)
+	}
+	return conn, nil
+}
+
+func (c *TCPConnector) Close() error {
+	return nil
+}