Add undeploy command: full inverse of deploy

Implements `mcp undeploy <service>` which tears down all infrastructure
for a service: removes mc-proxy routes, DNS records, TLS certificates,
stops and removes containers, releases allocated ports, and marks the
service inactive.

This fills the gap between `stop` (temporary pause) and `purge` (registry
cleanup). Undeploy is the complete teardown that returns the node to the
state before the service was deployed.

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

internal/agent/certs.go

@@ -176,6 +176,25 @@ func (p *CertProvisioner) issueCert(ctx context.Context, serviceName, commonName
 	return nil
 }
 
+// RemoveCert removes TLS certificate and key files for a service.
+func (p *CertProvisioner) RemoveCert(serviceName string) error {
+	if p == nil {
+		return nil
+	}
+
+	certPath := filepath.Join(p.certDir, serviceName+".pem")
+	keyPath := filepath.Join(p.certDir, serviceName+".key")
+
+	for _, path := range []string{certPath, keyPath} {
+		if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
+			return fmt.Errorf("remove %s: %w", path, err)
+		}
+	}
+
+	p.logger.Info("cert removed", "service", serviceName)
+	return nil
+}
+
 // certTimeRemaining returns the time until the leaf certificate at
 // path expires. Returns (0, false) if the cert cannot be read or parsed.
 func certTimeRemaining(path string) (time.Duration, bool) {

internal/agent/undeploy.go

@@ -0,0 +1,100 @@
+package agent
+
+import (
+	"context"
+	"fmt"
+
+	mcpv1 "git.wntrmute.dev/mc/mcp/gen/mcp/v1"
+	"git.wntrmute.dev/mc/mcp/internal/registry"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// UndeployService fully tears down a service: removes routes, DNS records,
+// TLS certificates, stops and removes containers, releases ports, and marks
+// the service inactive. This is the inverse of Deploy.
+func (a *Agent) UndeployService(ctx context.Context, req *mcpv1.UndeployServiceRequest) (*mcpv1.UndeployServiceResponse, error) {
+	a.Logger.Info("UndeployService", "service", req.GetName())
+
+	if req.GetName() == "" {
+		return nil, status.Error(codes.InvalidArgument, "service name is required")
+	}
+
+	serviceName := req.GetName()
+
+	components, err := registry.ListComponents(a.DB, serviceName)
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "list components: %v", err)
+	}
+
+	var results []*mcpv1.ComponentResult
+	dnsRemoved := false
+
+	for _, c := range components {
+		r := a.undeployComponent(ctx, serviceName, &c, &dnsRemoved)
+		results = append(results, r)
+	}
+
+	// Mark the service as inactive.
+	if err := registry.UpdateServiceActive(a.DB, serviceName, false); err != nil {
+		a.Logger.Warn("failed to mark service inactive", "service", serviceName, "err", err)
+	}
+
+	return &mcpv1.UndeployServiceResponse{Results: results}, nil
+}
+
+// undeployComponent tears down a single component. The dnsRemoved flag
+// tracks whether DNS has already been removed for this service (DNS is
+// per-service, not per-component).
+func (a *Agent) undeployComponent(ctx context.Context, serviceName string, c *registry.Component, dnsRemoved *bool) *mcpv1.ComponentResult {
+	containerName := ContainerNameFor(serviceName, c.Name)
+	r := &mcpv1.ComponentResult{Name: c.Name, Success: true}
+
+	// 1. Remove mc-proxy routes.
+	if len(c.Routes) > 0 && a.Proxy != nil {
+		if err := a.Proxy.RemoveRoutes(ctx, serviceName, c.Routes); err != nil {
+			a.Logger.Warn("failed to remove routes", "service", serviceName, "component", c.Name, "err", err)
+		}
+	}
+
+	// 2. Remove DNS records (once per service).
+	if len(c.Routes) > 0 && a.DNS != nil && !*dnsRemoved {
+		if err := a.DNS.RemoveRecord(ctx, serviceName); err != nil {
+			a.Logger.Warn("failed to remove DNS record", "service", serviceName, "err", err)
+		}
+		*dnsRemoved = true
+	}
+
+	// 3. Remove TLS certs (L7 routes only).
+	if hasL7Routes(c.Routes) && a.Certs != nil {
+		if err := a.Certs.RemoveCert(serviceName); err != nil {
+			a.Logger.Warn("failed to remove TLS cert", "service", serviceName, "err", err)
+		}
+	}
+
+	// 4. Stop and remove the container.
+	if err := a.Runtime.Stop(ctx, containerName); err != nil {
+		a.Logger.Info("stop container (ignored)", "container", containerName, "error", err)
+	}
+	if err := a.Runtime.Remove(ctx, containerName); err != nil {
+		a.Logger.Info("remove container (ignored)", "container", containerName, "error", err)
+	}
+
+	// 5. Release allocated ports.
+	if a.PortAlloc != nil {
+		hostPorts, err := registry.GetRouteHostPorts(a.DB, serviceName, c.Name)
+		if err == nil {
+			for _, port := range hostPorts {
+				a.PortAlloc.Release(port)
+			}
+		}
+	}
+
+	// 6. Update registry state.
+	if err := registry.UpdateComponentState(a.DB, serviceName, c.Name, "removed", "removed"); err != nil {
+		r.Success = false
+		r.Error = fmt.Sprintf("update state: %v", err)
+	}
+
+	return r
+}