monitor: see unikernel VMs + use canonical container naming

Two drift-reporting bugs:
1. The monitor listed only the podman runtime, so unikernel VMs always
   showed observed=unknown (false drift). It now takes a ContainerLister
   and the agent passes a merged lister (containers + VMs), mirroring
   listAllContainers.
2. The monitor computed the lookup name as service+"-"+component, which
   is wrong when component==service (the name collapses to just the
   service, e.g. "uktest"/"mc-proxy"). It now uses the canonical
   naming.ContainerNameFor — extracted to a shared package so the agent
   and monitor can't disagree.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

internal/monitor/monitor_test.go

@@ -227,6 +227,45 @@ func TestMonitorTickStateChange(t *testing.T) {
 	}
 }
 
+// TestMonitorTickCollapsedName guards the naming convention: when a
+// component's name equals its service, the container/VM name collapses to just
+// the service (e.g. "uktest", not "uktest-uktest"). The monitor must use
+// naming.ContainerNameFor to look it up, or it would report a running
+// component as "unknown" and raise false drift.
+func TestMonitorTickCollapsedName(t *testing.T) {
+	db := openTestDB(t)
+	logger := testLogger()
+	cfg := testMonitorConfig()
+
+	if err := registry.CreateService(db, "uktest", true, ""); err != nil {
+		t.Fatalf("create service: %v", err)
+	}
+	if err := registry.CreateComponent(db, &registry.Component{
+		Name: "uktest", Service: "uktest", Image: "img:v1",
+		Restart: "unless-stopped", DesiredState: "running", ObservedState: "unknown",
+	}); err != nil {
+		t.Fatalf("create component: %v", err)
+	}
+
+	// The runtime reports the collapsed name, as podman/QEMU actually do.
+	rt := &fakeRuntime{
+		containers: []runtime.ContainerInfo{
+			{Name: "uktest", State: "running"},
+		},
+	}
+
+	m := New(db, rt, cfg, "test-node", logger)
+	m.tick()
+
+	comp, err := registry.GetComponent(db, "uktest", "uktest")
+	if err != nil {
+		t.Fatalf("get component: %v", err)
+	}
+	if comp.ObservedState != "running" {
+		t.Fatalf("observed state: got %q, want %q (collapsed name not resolved)", comp.ObservedState, "running")
+	}
+}
+
 func TestMonitorStartStop(t *testing.T) {
 	db := openTestDB(t)
 	logger := testLogger()