feat(portforwarding): allow running script upon port forwarding success (#2399)

internal/portforward/interfaces.go

@@ -3,6 +3,7 @@ package portforward
 import (
 	"context"
 	"net/netip"
+	"os/exec"
 )
 
 type Service interface {
@@ -29,3 +30,8 @@ type Logger interface {
 	Warn(s string)
 	Error(s string)
 }
+
+type Cmder interface {
+	Start(cmd *exec.Cmd) (stdoutLines, stderrLines <-chan string,
+		waitError <-chan error, startErr error)
+}