P2.2-P2.9, P3.2-P3.10, P4.1-P4.3: Complete Phases 2, 3, and 4

11 work units built in parallel and merged:

Agent handlers (Phase 2):
- P2.2 Deploy: pull images, stop/remove/run containers, update registry
- P2.3 Lifecycle: stop/start/restart with desired_state tracking
- P2.4 Status: list (registry), live check (runtime), get status (drift+events)
- P2.5 Sync: receive desired state, reconcile unmanaged containers
- P2.6 File transfer: push/pull scoped to /srv/<service>/, path validation
- P2.7 Adopt: match <service>-* containers, derive component names
- P2.8 Monitor: continuous watch loop, drift/flap alerting, event pruning
- P2.9 Snapshot: VACUUM INTO database backup command

CLI commands (Phase 3):
- P3.2 Login, P3.3 Deploy, P3.4 Stop/Start/Restart
- P3.5 List/Ps/Status, P3.6 Sync, P3.7 Adopt
- P3.8 Service show/edit/export, P3.9 Push/Pull, P3.10 Node list/add/remove

Deployment artifacts (Phase 4):
- Systemd units (agent service + backup timer)
- Example configs (CLI + agent)
- Install script (idempotent)

All packages: build, vet, lint (0 issues), test (all pass).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cmd/mcp/service.go

@@ -1,9 +1,18 @@
 package main
 
 import (
+	"context"
 	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
 
+	mcpv1 "git.wntrmute.dev/kyle/mcp/gen/mcp/v1"
+	"git.wntrmute.dev/kyle/mcp/internal/config"
+	"git.wntrmute.dev/kyle/mcp/internal/servicedef"
+	toml "github.com/pelletier/go-toml/v2"
 	"github.com/spf13/cobra"
+	"google.golang.org/grpc"
 )
 
 func serviceCmd() *cobra.Command {
@@ -16,30 +25,204 @@ func serviceCmd() *cobra.Command {
 		Use:   "show <service>",
 		Short: "Print current spec from agent registry",
 		Args:  cobra.ExactArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
-			return fmt.Errorf("not implemented")
-		},
+		RunE:  runServiceShow,
 	}
 
 	edit := &cobra.Command{
 		Use:   "edit <service>",
 		Short: "Open service definition in $EDITOR",
 		Args:  cobra.ExactArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
-			return fmt.Errorf("not implemented")
-		},
+		RunE:  runServiceEdit,
 	}
 
 	export := &cobra.Command{
 		Use:   "export <service>",
 		Short: "Write agent registry spec to local service file",
 		Args:  cobra.ExactArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
-			return fmt.Errorf("not implemented")
-		},
+		RunE:  runServiceExport,
 	}
 	export.Flags().StringP("file", "f", "", "output file path")
 
 	cmd.AddCommand(show, edit, export)
 	return cmd
 }
+
+// findServiceNode checks the local service definition file first, then
+// queries all agents to locate which node runs the named service.
+func findServiceNode(cfg *config.CLIConfig, serviceName string) (string, string, error) {
+	defPath := filepath.Join(cfg.Services.Dir, serviceName+".toml")
+	if def, err := servicedef.Load(defPath); err == nil {
+		for _, n := range cfg.Nodes {
+			if n.Name == def.Node {
+				return n.Name, n.Address, nil
+			}
+		}
+		return "", "", fmt.Errorf("node %q from service def not found in config", def.Node)
+	}
+
+	for _, n := range cfg.Nodes {
+		client, conn, err := dialAgent(n.Address, cfg)
+		if err != nil {
+			continue
+		}
+		resp, err := client.ListServices(context.Background(), &mcpv1.ListServicesRequest{})
+		_ = conn.Close()
+		if err != nil {
+			continue
+		}
+		for _, svc := range resp.GetServices() {
+			if svc.GetName() == serviceName {
+				return n.Name, n.Address, nil
+			}
+		}
+	}
+
+	return "", "", fmt.Errorf("service %q not found on any node", serviceName)
+}
+
+// fetchServiceInfo dials the agent at address, calls ListServices, and returns
+// the matching ServiceInfo. The caller must close the returned connection.
+func fetchServiceInfo(address string, cfg *config.CLIConfig, serviceName string) (*mcpv1.ServiceInfo, *grpc.ClientConn, error) {
+	client, conn, err := dialAgent(address, cfg)
+	if err != nil {
+		return nil, nil, fmt.Errorf("dial agent: %w", err)
+	}
+
+	resp, err := client.ListServices(context.Background(), &mcpv1.ListServicesRequest{})
+	if err != nil {
+		_ = conn.Close()
+		return nil, nil, fmt.Errorf("list services: %w", err)
+	}
+
+	for _, svc := range resp.GetServices() {
+		if svc.GetName() == serviceName {
+			return svc, conn, nil
+		}
+	}
+
+	_ = conn.Close()
+	return nil, nil, fmt.Errorf("service %q not found on agent", serviceName)
+}
+
+// serviceInfoToSpec converts a ServiceInfo (runtime view) to a ServiceSpec
+// (config view) for use with servicedef.FromProto.
+func serviceInfoToSpec(info *mcpv1.ServiceInfo) *mcpv1.ServiceSpec {
+	spec := &mcpv1.ServiceSpec{
+		Name:   info.GetName(),
+		Active: info.GetActive(),
+	}
+	for _, c := range info.GetComponents() {
+		spec.Components = append(spec.Components, &mcpv1.ComponentSpec{
+			Name:  c.GetName(),
+			Image: c.GetImage(),
+		})
+	}
+	return spec
+}
+
+func runServiceShow(_ *cobra.Command, args []string) error {
+	serviceName := args[0]
+
+	cfg, err := config.LoadCLIConfig(cfgPath)
+	if err != nil {
+		return fmt.Errorf("load config: %w", err)
+	}
+
+	_, address, err := findServiceNode(cfg, serviceName)
+	if err != nil {
+		return err
+	}
+
+	svc, conn, err := fetchServiceInfo(address, cfg, serviceName)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = conn.Close() }()
+
+	def := servicedef.FromProto(serviceInfoToSpec(svc), "")
+	data, err := toml.Marshal(def)
+	if err != nil {
+		return fmt.Errorf("marshal service: %w", err)
+	}
+	fmt.Print(string(data))
+	return nil
+}
+
+func runServiceEdit(_ *cobra.Command, args []string) error {
+	serviceName := args[0]
+
+	cfg, err := config.LoadCLIConfig(cfgPath)
+	if err != nil {
+		return fmt.Errorf("load config: %w", err)
+	}
+
+	filePath := filepath.Join(cfg.Services.Dir, serviceName+".toml")
+
+	// If local file does not exist, export from agent first.
+	if _, err := os.Stat(filePath); os.IsNotExist(err) {
+		nodeName, address, err := findServiceNode(cfg, serviceName)
+		if err != nil {
+			return fmt.Errorf("find service for export: %w", err)
+		}
+
+		svc, conn, err := fetchServiceInfo(address, cfg, serviceName)
+		if err != nil {
+			return err
+		}
+		defer func() { _ = conn.Close() }()
+
+		def := servicedef.FromProto(serviceInfoToSpec(svc), nodeName)
+		if err := servicedef.Write(filePath, def); err != nil {
+			return fmt.Errorf("write service def: %w", err)
+		}
+		_, _ = fmt.Fprintf(os.Stderr, "Exported %s from agent to %s\n", serviceName, filePath)
+	}
+
+	editor := os.Getenv("EDITOR")
+	if editor == "" {
+		editor = os.Getenv("VISUAL")
+	}
+	if editor == "" {
+		editor = "vi"
+	}
+
+	cmd := exec.Command(editor, filePath) //nolint:gosec // editor from trusted env
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	return cmd.Run()
+}
+
+func runServiceExport(cmd *cobra.Command, args []string) error {
+	serviceName := args[0]
+
+	cfg, err := config.LoadCLIConfig(cfgPath)
+	if err != nil {
+		return fmt.Errorf("load config: %w", err)
+	}
+
+	nodeName, address, err := findServiceNode(cfg, serviceName)
+	if err != nil {
+		return err
+	}
+
+	svc, conn, err := fetchServiceInfo(address, cfg, serviceName)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = conn.Close() }()
+
+	def := servicedef.FromProto(serviceInfoToSpec(svc), nodeName)
+
+	outPath, _ := cmd.Flags().GetString("file")
+	if outPath == "" {
+		outPath = filepath.Join(cfg.Services.Dir, serviceName+".toml")
+	}
+
+	if err := servicedef.Write(outPath, def); err != nil {
+		return fmt.Errorf("write service def: %w", err)
+	}
+	fmt.Printf("Exported %s to %s\n", serviceName, outPath)
+	return nil
+}