feat(ssh+cli): Support SSH CLI on machine init and add commands (#173)

* Add SSHCLIRemote type with buildSSHArgs

Implement's Executor interface (Run, Stream, Close)

* Add UseSSHCLI field to RemoteMachine struct

Allow us to differentiate regular ssh from ssh+cli.

* Parse ssh+cli:// scheme on machine init/add

* Support SSH CLI when provisioning

* Update docs to reflect ssh+cli:// support

* Revert removal of `init` examples

Fixes copy & pasta mistake when documenting the new ssh+cli connection
methods.

cmd/uncloud/machine/add.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/netip"
+	"strings"
 	"time"
 
 	"github.com/cenkalti/backoff/v4"
@@ -34,19 +35,31 @@ func NewAddCommand() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "add [USER@]HOST[:PORT]",
 		Short: "Add a remote machine to a cluster.",
-		Args:  cobra.ExactArgs(1),
+		Long: `Add a new machine to an existing Uncloud cluster.
+
+Connection methods:
+  ssh://user@host       - Use built-in SSH library (default, no prefix required)
+  ssh+cli://user@host   - Use system SSH command (supports ProxyJump, SSH config)`,
+		Args: cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
 
-			user, host, port, err := config.SSHDestination(args[0]).Parse()
+			// Determine if SSH CLI needs to be used and strip scheme
+			destination := args[0]
+			useSSHCLI := strings.HasPrefix(destination, "ssh+cli://")
+			destination = strings.TrimPrefix(destination, "ssh+cli://")
+			destination = strings.TrimPrefix(destination, "ssh://")
+
+			user, host, port, err := config.SSHDestination(destination).Parse()
 			if err != nil {
 				return fmt.Errorf("parse remote machine: %w", err)
 			}
 			remoteMachine := &cli.RemoteMachine{
-				User:    user,
-				Host:    host,
-				Port:    port,
-				KeyPath: opts.sshKey,
+				User:      user,
+				Host:      host,
+				Port:      port,
+				KeyPath:   opts.sshKey,
+				UseSSHCLI: useSSHCLI,
 			}
 
 			return add(cmd.Context(), uncli, remoteMachine, opts)

cmd/uncloud/machine/init.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/netip"
+	"strings"
 
 	"github.com/docker/compose/v2/pkg/progress"
 	"github.com/psviderski/uncloud/cmd/uncloud/caddy"
@@ -34,8 +35,12 @@ func NewInitCommand() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "init [USER@HOST:PORT]",
 		Short: "Initialise a new cluster with a remote machine as the first member.",
-		Long: "Initialise a new cluster by setting up a remote machine as the first member.\n" +
-			"This command creates a new context in your Uncloud config to manage the cluster.",
+		Long: `Initialise a new cluster by setting up a remote machine as the first member.
+This command creates a new context in your Uncloud config to manage the cluster.
+
+Connection methods:
+  ssh://user@host       - Use built-in SSH library (default, no prefix required)
+  ssh+cli://user@host   - Use system SSH command (supports ProxyJump, SSH config)`,
 		Example: `  # Initialise a new cluster with default settings.
   uc machine init root@<your-server-ip>
 
@@ -55,15 +60,22 @@ func NewInitCommand() *cobra.Command {
 
 			var remoteMachine *cli.RemoteMachine
 			if len(args) > 0 {
-				user, host, port, err := config.SSHDestination(args[0]).Parse()
+				// Determine if SSH CLI is requested and strip scheme
+				destination := args[0]
+				useSSHCLI := strings.HasPrefix(destination, "ssh+cli://")
+				destination = strings.TrimPrefix(destination, "ssh+cli://")
+				destination = strings.TrimPrefix(destination, "ssh://")
+
+				user, host, port, err := config.SSHDestination(destination).Parse()
 				if err != nil {
 					return fmt.Errorf("parse remote machine: %w", err)
 				}
 				remoteMachine = &cli.RemoteMachine{
-					User:    user,
-					Host:    host,
-					Port:    port,
-					KeyPath: opts.sshKey,
+					User:      user,
+					Host:      host,
+					Port:      port,
+					KeyPath:   opts.sshKey,
+					UseSSHCLI: useSSHCLI,
 				}
 			}