feat: CLI-Skeleton mit version/serve/check und Makefile

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NBHF4R9EAejDJUMdwr6C68

cmd/vpnportal/main.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+const usage = `vpnportal — VPN-Konfig-Portal für OPNsense
+
+Aufruf:
+  vpnportal serve   [--config PFAD]   Portal starten (Default)
+  vpnportal check   [--config PFAD] [--test-auth BENUTZER]
+  vpnportal version
+
+Optionen:
+  --config PFAD   Pfad zur Konfigurationsdatei (Default: /etc/vpnportal/config.yaml)
+`
+
+func main() {
+	os.Exit(run(os.Args[1:], os.Stdout, os.Stderr))
+}
+
+func run(args []string, stdout, stderr io.Writer) int {
+	cmd := "serve"
+	rest := args
+	if len(args) > 0 && len(args[0]) > 0 && args[0][0] != '-' {
+		cmd, rest = args[0], args[1:]
+	}
+
+	switch cmd {
+	case "version":
+		fmt.Fprintln(stdout, versionString())
+		return 0
+	case "serve":
+		return runServe(rest, stdout, stderr)
+	case "check":
+		return runCheck(rest, stdout, stderr)
+	case "help", "-h", "--help":
+		fmt.Fprint(stdout, usage)
+		return 0
+	default:
+		fmt.Fprintf(stderr, "Unbekanntes Kommando: %s\n\n%s", cmd, usage)
+		return 2
+	}
+}