Remove proboctl internal admin CLI

The set-branding functionality it provided is no longer needed.

Signed-off-by: Émile Ré <emile@getprobo.com>

cmd/proboctl/main.go

@@ -1,35 +0,0 @@
-// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
-//
-// Permission to use, copy, modify, and/or distribute this software for any
-// purpose with or without fee is hereby granted, provided that the above
-// copyright notice and this permission notice appear in all copies.
-//
-// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
-// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
-// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
-// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
-// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
-// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
-// PERFORMANCE OF THIS SOFTWARE.
-
-package main
-
-import (
-	"fmt"
-	"os"
-
-	"go.probo.inc/probo/pkg/proboctl"
-)
-
-var (
-	version string = "unknown"
-)
-
-func main() {
-	cmd := proboctl.NewRootCmd(version)
-
-	if err := cmd.Execute(); err != nil {
-		fmt.Fprintf(os.Stderr, "Error: %s\n", err)
-		os.Exit(1)
-	}
-}