fix(create): drop --image Value default so the empty-check survives

Value: cfg.DefaultContainerImage made cmd.String("image") never empty,
which killed the `containerImage == ""` branch in makeContainerImage
and spuriously triggered the `name == default` fallback for `--name foo`
alone. The Usage string already shows the default.

Signed-off-by: Luca Di Maio <luca.dimaio1@gmail.com>

internal/cli/create.go

@@ -45,7 +45,10 @@ Examples:
 					"image to use for the container (default: %s)",
 					cfg.DefaultContainerImage,
 				),
-				Value: cfg.DefaultContainerImage,
+				// No Value default: leaving it empty lets makeContainerImage's
+				// "no clone & no image" branch select cfg.DefaultContainerImage,
+				// which is what triggers the default-name fallback. Setting
+				// Value here would defeat that check (shell parity).
 			},
 			&cli.StringFlag{
 				Name:    "name",