refactor: migrate docker-options subcommands to go

Ports the user-facing CLI subcommands and lifecycle triggers from bash to go, mirroring the layout used by the ports plugin. The on-disk format (`DOCKER_OPTIONS_BUILD/DEPLOY/RUN` files), the `docker-args-build/deploy/run` triggers, and every exported helper consumed by other plugins are unchanged. Reserves the `--process` and `--global` flags on add, remove, and clear so usage today exits with a not-yet-implemented error and the surface is locked in ahead of the process-scoping work tracked in #2441.

plugins/docker-options/src/commands/commands.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/common"
+)
+
+const (
+	helpHeader = `Usage: dokku docker-options[:COMMAND]
+
+Manage docker options for an app
+
+Additional commands:`
+
+	helpContent = `
+    docker-options:add <app> <phase(s)> OPTION, Add Docker option to app for phase (comma separated phase list)
+    docker-options:clear <app> [phase(s)], Clear a docker options from application with an optional phase (comma separated phase list)
+    docker-options:remove <app> <phase(s)> OPTION, Remove Docker option from app for phase (comma separated phase list)
+    docker-options:report [<app>] [<flag>], Displays a docker options report for one or more apps`
+)
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+
+	cmd := flag.Arg(0)
+	switch cmd {
+	case "docker-options", "docker-options:help":
+		usage()
+	case "help":
+		result, err := common.CallExecCommand(common.ExecCommandInput{
+			Command: "ps",
+			Args:    []string{"-o", "command=", strconv.Itoa(os.Getppid())},
+		})
+		if err == nil && strings.Contains(result.StdoutContents(), "--all") {
+			fmt.Println(helpContent)
+		} else {
+			fmt.Print("\n    docker-options, Manage docker options for an app\n")
+		}
+	default:
+		dokkuNotImplementExitCode, err := strconv.Atoi(os.Getenv("DOKKU_NOT_IMPLEMENTED_EXIT"))
+		if err != nil {
+			fmt.Println("failed to retrieve DOKKU_NOT_IMPLEMENTED_EXIT environment variable")
+			dokkuNotImplementExitCode = 10
+		}
+		os.Exit(dokkuNotImplementExitCode)
+	}
+}
+
+func usage() {
+	common.CommandUsage(helpHeader, helpContent)
+}