cmd/headscale/cli: add grpcRun wrapper for gRPC client lifecycle

Add a grpcRun helper that wraps cobra RunFuncs, injecting a ready
gRPC client and context. The connection lifecycle (cancel, close)
is managed by the wrapper, eliminating the duplicated 3-line
boilerplate (newHeadscaleCLIWithConfig + defer cancel + defer
conn.Close) from 22 command handlers across 7 files.

Three call sites are intentionally left unconverted:
- backfillNodeIPsCmd: creates the client only after user confirmation
- getPolicy/setPolicy: conditionally use gRPC vs direct DB access

cmd/headscale/cli/debug.go

@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"context"
 	"fmt"
 
 	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
@@ -59,7 +60,7 @@ var debugCmd = &cobra.Command{
 var createNodeCmd = &cobra.Command{
 	Use:   "create-node",
 	Short: "Create a node that can be registered with `nodes register <>` command",
-	Run: func(cmd *cobra.Command, args []string) {
+	Run: grpcRun(func(ctx context.Context, client v1.HeadscaleServiceClient, cmd *cobra.Command, args []string) {
 		output, _ := cmd.Flags().GetString("output")
 
 		user, err := cmd.Flags().GetString("user")
@@ -67,10 +68,6 @@ var createNodeCmd = &cobra.Command{
 			ErrorOutput(err, fmt.Sprintf("Error getting user: %s", err), output)
 		}
 
-		ctx, client, conn, cancel := newHeadscaleCLIWithConfig()
-		defer cancel()
-		defer conn.Close()
-
 		name, err := cmd.Flags().GetString("name")
 		if err != nil {
 			ErrorOutput(
@@ -124,5 +121,5 @@ var createNodeCmd = &cobra.Command{
 		}
 
 		SuccessOutput(response.GetNode(), "Node created", output)
-	},
+	}),
 }