Add mcproxyctl CLI for gRPC admin API

Introduces a new command-line tool for managing mc-proxy via the gRPC
admin API over Unix socket. Commands include route and firewall rule
CRUD operations, health checks, and status queries.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/mcproxyctl/root.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"context"
+	"os"
+
+	"github.com/spf13/cobra"
+
+	"git.wntrmute.dev/kyle/mc-proxy/client/mcproxy"
+)
+
+const defaultSocketPath = "/var/run/mc-proxy.sock"
+
+type contextKey string
+
+const clientKey contextKey = "client"
+
+func rootCmd() *cobra.Command {
+	var socketPath string
+
+	cmd := &cobra.Command{
+		Use:   "mcproxyctl",
+		Short: "Control a running mc-proxy instance",
+		Long:  "mcproxyctl is a command-line tool for administrating a running mc-proxy instance via the gRPC admin API.",
+		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+			// Skip client setup for help commands
+			if cmd.Name() == "help" || cmd.Name() == "completion" {
+				return nil
+			}
+
+			// Environment variable override
+			if envSocket := os.Getenv("MCPROXY_SOCKET"); envSocket != "" && socketPath == defaultSocketPath {
+				socketPath = envSocket
+			}
+
+			client, err := mcproxy.Dial(socketPath)
+			if err != nil {
+				return err
+			}
+
+			ctx := context.WithValue(cmd.Context(), clientKey, client)
+			cmd.SetContext(ctx)
+			return nil
+		},
+		PersistentPostRunE: func(cmd *cobra.Command, args []string) error {
+			client := clientFromContext(cmd.Context())
+			if client != nil {
+				return client.Close()
+			}
+			return nil
+		},
+		SilenceUsage: true,
+	}
+
+	cmd.PersistentFlags().StringVarP(&socketPath, "socket", "s", defaultSocketPath, "Unix socket path")
+
+	cmd.AddCommand(statusCmd())
+	cmd.AddCommand(healthCmd())
+	cmd.AddCommand(routesCmd())
+	cmd.AddCommand(firewallCmd())
+
+	return cmd
+}
+
+func clientFromContext(ctx context.Context) *mcproxy.Client {
+	if ctx == nil {
+		return nil
+	}
+	client, _ := ctx.Value(clientKey).(*mcproxy.Client)
+	return client
+}