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/agent/names.go

@@ -1,34 +1,14 @@
 package agent
 
-import "strings"
+import "git.wntrmute.dev/mc/mcp/internal/naming"
 
-// ContainerNameFor returns the expected container name for a service and
-// component. For single-component services where the component name equals
-// the service name, the container name is just the service name (e.g.,
-// "mc-proxy" not "mc-proxy-mc-proxy").
+// ContainerNameFor is a convenience alias for naming.ContainerNameFor (the
+// canonical convention, shared with the monitor).
 func ContainerNameFor(service, component string) string {
-	if service == component {
-		return service
-	}
-	return service + "-" + component
+	return naming.ContainerNameFor(service, component)
 }
 
-// SplitContainerName splits a container name into service and component parts.
-// It checks known service names first to handle names like "mc-proxy" where a
-// naive split on "-" would produce the wrong result. If no known service
-// matches, it falls back to splitting on the first "-".
+// SplitContainerName is a convenience alias for naming.SplitContainerName.
 func SplitContainerName(name string, knownServices map[string]bool) (service, component string) {
-	if knownServices[name] {
-		return name, name
-	}
-	for svc := range knownServices {
-		prefix := svc + "-"
-		if strings.HasPrefix(name, prefix) && len(name) > len(prefix) {
-			return svc, name[len(prefix):]
-		}
-	}
-	if i := strings.Index(name, "-"); i >= 0 {
-		return name[:i], name[i+1:]
-	}
-	return name, name
+	return naming.SplitContainerName(name, knownServices)
 }