Preflight names the carried image for what it is

It said 'control plane' beside a builder's tag, which is the sort of line that
teaches a reader the wrong thing about what the installer carries.

internal/bootstrap/preflight.go

@@ -65,7 +65,7 @@ func Preflight(ctx context.Context, o Options, d Deps, say func(string)) ([]byte
 				"Rebuild the installer with a tagged image: `make bootstrap IMAGE=<name>:<tag>`",
 			carriedID)
 	}
-	say(fmt.Sprintf("  control plane     %s carried (the archive calls it %s)", tag, carriedID))
+	say(fmt.Sprintf("  builder           %s carried (the archive calls it %s)", tag, carriedID))
 
 	// 2. Is the template there, and is it a substrate?
 	template, err := os.ReadFile(o.Template)